A JavaScript library for arbitrary-precision arithmetic.
See the README on GitHub for a quick-start introduction.
In all examples below, var
and semicolons are not shown, and if a commented-out
value is in quotes it means toString
has been called on the preceding expression.
BigNumber(value [, base]) ⇒ BigNumber
value
0
, ±Infinity
and
NaN
.
15
significant digits are
considered invalid (if ERRORS
is true) as calling
toString
or valueOf
on
such numbers may not result in the intended value.
console.log( 823456789123456.3 ); // 823456789123456.2
'0xff'
, are valid, as are
string values with the octal and binary prefixs '0o'
and '0b'
.
String values in octal literal form without the prefix will be interpreted as
decimals, e.g. '011'
is interpreted as 11, not 9.
10
to 36
, lower and/or upper case letters can be
used to represent values from 10
to 35
.
a-z
represents values from 10
to
35
, A-Z
from 36
to 61
, and
$
and _
represent 62
and 63
respectively
(this can be changed by editing the ALPHABET
variable near the top of the
source file).
base
2
to 64
inclusive
value
.base
is omitted, or is null
or undefined
, base
10
is assumed.
Returns a new instance of a BigNumber object.
If a base is specified, the value is rounded according to
the current DECIMAL_PLACES
and
ROUNDING_MODE
configuration.
See Errors for the treatment of an invalid value
or
base
.
x = new BigNumber(9) // '9' y = new BigNumber(x) // '9' // 'new' is optional if ERRORS is false BigNumber(435.345) // '435.345' new BigNumber('5032485723458348569331745.33434346346912144534543') new BigNumber('4.321e+4') // '43210' new BigNumber('-735.0918e-430') // '-7.350918e-428' new BigNumber(Infinity) // 'Infinity' new BigNumber(NaN) // 'NaN' new BigNumber('.5') // '0.5' new BigNumber('+2') // '2' new BigNumber(-10110100.1, 2) // '-180.5' new BigNumber(-0b10110100.1) // '-180.5' new BigNumber('123412421.234324', 5) // '607236.557696' new BigNumber('ff.8', 16) // '255.5' new BigNumber('0xff.8') // '255.5'
The following throws 'not a base 2 number'
if
ERRORS
is true, otherwise it returns a BigNumber with value
NaN
.
new BigNumber(9, 2)
The following throws 'number type has more than 15 significant digits'
if
ERRORS
is true, otherwise it returns a BigNumber with value
96517860459076820
.
new BigNumber(96517860459076817.4395)
The following throws 'not a number'
if ERRORS
is true, otherwise it returns a BigNumber with value NaN
.
new BigNumber('blurgh')
A value is only rounded by the constructor if a base is specified.
BigNumber.config({ DECIMAL_PLACES: 5 }) new BigNumber(1.23456789) // '1.23456789' new BigNumber(1.23456789, 10) // '1.23457'
The static methods of a BigNumber constructor.
.another([obj]) ⇒ BigNumber constructor
obj
: object
Returns a new independent BigNumber constructor with configuration as described by
obj
(see config
), or with the default
configuration if obj
is null
or undefined
.
BigNumber.config({ DECIMAL_PLACES: 5 }) BN = BigNumber.another({ DECIMAL_PLACES: 9 }) x = new BigNumber(1) y = new BN(1) x.div(3) // 0.33333 y.div(3) // 0.333333333 // BN = BigNumber.another({ DECIMAL_PLACES: 9 }) is equivalent to: BN = BigNumber.another() BN.config({ DECIMAL_PLACES: 9 })
set([obj]) ⇒ object
obj
: object: an object that contains some or all of the following
properties.
Configures the settings for this particular BigNumber constructor.
Note: the configuration can also be supplied as an argument list, see below.
DECIMAL_PLACES
0
to 1e+9
inclusive20
BigNumber.config({ DECIMAL_PLACES: 5 }) BigNumber.set({ DECIMAL_PLACES: 5 }) // equivalent BigNumber.config(5) // equivalent
ROUNDING_MODE
0
to 8
inclusive4
(ROUND_HALF_UP
)
round
,
toExponential
,
toFixed
,
toFormat
and
toPrecision
.
BigNumber.config({ ROUNDING_MODE: 0 }) BigNumber.config(null, BigNumber.ROUND_UP) // equivalent
EXPONENTIAL_AT
0
to 1e+9
inclusive, or
-1e+9
to 0
inclusive, integer
0
to 1e+9
inclusive ][-7, 20]
toString
returns exponential notation.
[-7, 20]
.
BigNumber.config({ EXPONENTIAL_AT: 2 }) new BigNumber(12.3) // '12.3' e is only 1 new BigNumber(123) // '1.23e+2' new BigNumber(0.123) // '0.123' e is only -1 new BigNumber(0.0123) // '1.23e-2' BigNumber.config({ EXPONENTIAL_AT: [-7, 20] }) new BigNumber(123456789) // '123456789' e is only 8 new BigNumber(0.000000123) // '1.23e-7' // Almost never return exponential notation: BigNumber.config({ EXPONENTIAL_AT: 1e+9 }) // Always return exponential notation: BigNumber.config({ EXPONENTIAL_AT: 0 })
EXPONENTIAL_AT
, the toFixed
method
will always return a value in normal notation and the toExponential
method
will always return a value in exponential form.
toString
with a base argument, e.g. toString(10)
, will
also always return normal notation.
RANGE
1
to 1e+9
inclusive, or
-1e+9
to -1
inclusive, integer
1
to 1e+9
inclusive ][-1e+9, 1e+9]
Infinity
and underflow to
zero occurs.
Infinity
and those with a
negative exponent of greater magnitude become zero.
Infinity
, use [-324, 308]
.
BigNumber.config({ RANGE: 500 }) BigNumber.config().RANGE // [ -500, 500 ] new BigNumber('9.999e499') // '9.999e+499' new BigNumber('1e500') // 'Infinity' new BigNumber('1e-499') // '1e-499' new BigNumber('1e-500') // '0' BigNumber.config({ RANGE: [-3, 4] }) new BigNumber(99999) // '99999' e is only 4 new BigNumber(100000) // 'Infinity' e is 5 new BigNumber(0.001) // '0.01' e is only -3 new BigNumber(0.0001) // '0' e is -4
9.999...e+1000000000
.1e-1000000000
.
ERRORS
true
, false
, 0
or
1
.true
ERRORS
is false, no errors will be thrown.
BigNumber.config({ ERRORS: false })
CRYPTO
true
, false
, 0
or
1
.false
CRYPTO
is set to true
then the
random
method will generate random digits using
crypto.getRandomValues
in browsers that support it, or
crypto.randomBytes
if using a version of Node.js that supports it.
CRYPTO
to true
will fail, and if ERRORS
is true
an exception will be thrown.
CRYPTO
is false
then the source of randomness used will be
Math.random
(which is assumed to generate at least 30
bits of
randomness).
random
.BigNumber.config({ CRYPTO: true }) BigNumber.config().CRYPTO // true BigNumber.random() // 0.54340758610486147524
MODULO_MODE
0
to 9
inclusive1
(ROUND_DOWN
)
a mod n
.q = a / n
, is calculated according to the
ROUNDING_MODE
that corresponds to the chosen
MODULO_MODE
.
r
, is calculated as: r = a - n * q
.Property | Value | Description |
---|---|---|
ROUND_UP | 0 | The remainder is positive if the dividend is negative, otherwise it is negative. |
ROUND_DOWN | 1 |
The remainder has the same sign as the dividend. This uses 'truncating division' and matches the behaviour of JavaScript's remainder operator % .
|
ROUND_FLOOR | 3 |
The remainder has the same sign as the divisor. This matches Python's % operator.
|
ROUND_HALF_EVEN | 6 | The IEEE 754 remainder function. |
EUCLID | 9 |
The remainder is always positive. Euclidian division: q = sign(n) * floor(a / abs(n))
|
modulo
.BigNumber.config({ MODULO_MODE: BigNumber.EUCLID }) BigNumber.config({ MODULO_MODE: 9 }) // equivalent
POW_PRECISION
0
to 1e+9
inclusive.0
0
, the number of signifcant digits will not be limited.toPower
.BigNumber.config({ POW_PRECISION: 100 })
FORMAT
FORMAT
object configures the format of the string returned by the
toFormat
method.
FORMAT
object that are
recognised, and their default values.
FORMAT
object will not be checked for validity. The existing
FORMAT
object will simply be replaced by the object that is passed in.
Note that all the properties shown below do not have to be included.
toFormat
for examples of usage.BigNumber.config({ FORMAT: { // the decimal separator decimalSeparator: '.', // the grouping separator of the integer part groupSeparator: ',', // the primary grouping size of the integer part groupSize: 3, // the secondary grouping size of the integer part secondaryGroupSize: 0, // the grouping separator of the fraction part fractionGroupSeparator: ' ', // the grouping size of the fraction part fractionGroupSize: 0 } });
Returns an object with the above properties and their current values.
If the value to be assigned to any of the above properties is null
or
undefined
it is ignored.
See Errors for the treatment of invalid values.
BigNumber.config({ DECIMAL_PLACES: 40, ROUNDING_MODE: BigNumber.ROUND_HALF_CEIL, EXPONENTIAL_AT: [-10, 20], RANGE: [-500, 500], ERRORS: true, CRYPTO: true, MODULO_MODE: BigNumber.ROUND_FLOOR, POW_PRECISION: 80, FORMAT: { groupSize: 3, groupSeparator: ' ', decimalSeparator: ',' } }); // Alternatively but equivalently (excluding FORMAT): BigNumber.config( 40, 7, [-10, 20], 500, 1, 1, 3, 80 ) obj = BigNumber.config(); obj.ERRORS // true obj.RANGE // [-500, 500]
.max([arg1 [, arg2, ...]]) ⇒ BigNumber
arg1
, arg2
, ...: number|string|BigNumber
See BigNumber
for further parameter details.
Returns a BigNumber whose value is the maximum of arg1
,
arg2
,... .
The argument to this method can also be an array of values.
The return value is always exact and unrounded.
x = new BigNumber('3257869345.0378653') BigNumber.max(4e9, x, '123456789.9') // '4000000000' arr = [12, '13', new BigNumber(14)] BigNumber.max(arr) // '14'
.min([arg1 [, arg2, ...]]) ⇒ BigNumber
arg1
, arg2
, ...: number|string|BigNumber
See BigNumber
for further parameter details.
Returns a BigNumber whose value is the minimum of arg1
,
arg2
,... .
The argument to this method can also be an array of values.
The return value is always exact and unrounded.
x = new BigNumber('3257869345.0378653') BigNumber.min(4e9, x, '123456789.9') // '123456789.9' arr = [2, new BigNumber(-14), '-15.9999', -12] BigNumber.min(arr) // '-15.9999'
.random([dp]) ⇒ BigNumber
dp
: number: integer, 0
to 1e+9
inclusive
Returns a new BigNumber with a pseudo-random value equal to or greater than 0
and
less than 1
.
The return value will have dp
decimal places (or less if trailing zeros are
produced).
If dp
is omitted then the number of decimal places will default to the current
DECIMAL_PLACES
setting.
Depending on the value of this BigNumber constructor's
CRYPTO
setting and the support for the
crypto
object in the host environment, the random digits of the return value are
generated by either Math.random
(fastest), crypto.getRandomValues
(Web Cryptography API in recent browsers) or crypto.randomBytes
(Node.js).
If CRYPTO
is true
, i.e. one of the
crypto
methods is to be used, the value of a returned BigNumber should be
cryptographically-secure and statistically indistinguishable from a random value.
BigNumber.config({ DECIMAL_PLACES: 10 }) BigNumber.random() // '0.4117936847' BigNumber.random(20) // '0.78193327636914089009'
The library's enumerated rounding modes are stored as properties of the constructor.
(They are not referenced internally by the library itself.)
Rounding modes 0
to 6
(inclusive) are the same as those of Java's
BigDecimal class.
Property | Value | Description |
---|---|---|
ROUND_UP | 0 | Rounds away from zero |
ROUND_DOWN | 1 | Rounds towards zero |
ROUND_CEIL | 2 | Rounds towards Infinity |
ROUND_FLOOR | 3 | Rounds towards -Infinity |
ROUND_HALF_UP | 4 |
Rounds towards nearest neighbour. If equidistant, rounds away from zero |
ROUND_HALF_DOWN | 5 |
Rounds towards nearest neighbour. If equidistant, rounds towards zero |
ROUND_HALF_EVEN | 6 |
Rounds towards nearest neighbour. If equidistant, rounds towards even neighbour |
ROUND_HALF_CEIL | 7 |
Rounds towards nearest neighbour. If equidistant, rounds towards Infinity
|
ROUND_HALF_FLOOR | 8 |
Rounds towards nearest neighbour. If equidistant, rounds towards -Infinity
|
BigNumber.config({ ROUNDING_MODE: BigNumber.ROUND_CEIL }) BigNumber.config({ ROUNDING_MODE: 2 }) // equivalent
The methods inherited by a BigNumber instance from its constructor's prototype object.
A BigNumber is immutable in the sense that it is not changed by its methods.
The treatment of ±0
, ±Infinity
and NaN
is
consistent with how JavaScript treats these values.
Many method names have a shorter alias.
(Internally, the library always uses the shorter method names.)
.abs() ⇒ BigNumber
Returns a BigNumber whose value is the absolute value, i.e. the magnitude, of the value of this BigNumber.
The return value is always exact and unrounded.
x = new BigNumber(-0.8) y = x.absoluteValue() // '0.8' z = y.abs() // '0.8'
.ceil() ⇒ BigNumber
Returns a BigNumber whose value is the value of this BigNumber rounded to
a whole number in the direction of positive Infinity
.
x = new BigNumber(1.3) x.ceil() // '2' y = new BigNumber(-1.8) y.ceil() // '-1'
.cmp(n [, base]) ⇒ number
n
: number|string|BigNumber
base
: number
See BigNumber for further parameter details.
Returns | |
---|---|
1 |
If the value of this BigNumber is greater than the value of n |
-1 |
If the value of this BigNumber is less than the value of n |
0 |
If this BigNumber and n have the same value |
null |
If the value of either this BigNumber or n is NaN |
x = new BigNumber(Infinity) y = new BigNumber(5) x.comparedTo(y) // 1 x.comparedTo(x.minus(1)) // 0 y.cmp(NaN) // null y.cmp('110', 2) // -1
.dp() ⇒ number
Return the number of decimal places of the value of this BigNumber, or null
if
the value of this BigNumber is ±Infinity
or NaN
.
x = new BigNumber(123.45) x.decimalPlaces() // 2 y = new BigNumber('9.9e-101') y.dp() // 102
.div(n [, base]) ⇒ BigNumber
n
: number|string|BigNumber
base
: number
See BigNumber for further parameter details.
Returns a BigNumber whose value is the value of this BigNumber divided by
n
, rounded according to the current
DECIMAL_PLACES
and
ROUNDING_MODE
configuration.
x = new BigNumber(355) y = new BigNumber(113) x.dividedBy(y) // '3.14159292035398230088' x.div(5) // '71' x.div(47, 16) // '5'
.divToInt(n [, base]) ⇒
BigNumber
n
: number|string|BigNumber
base
: number
See BigNumber for further parameter details.
Return a BigNumber whose value is the integer part of dividing the value of this BigNumber by
n
.
x = new BigNumber(5) y = new BigNumber(3) x.dividedToIntegerBy(y) // '1' x.divToInt(0.7) // '7' x.divToInt('0.f', 16) // '5'
.eq(n [, base]) ⇒ boolean
n
: number|string|BigNumber
base
: number
See BigNumber for further parameter details.
Returns true
if the value of this BigNumber equals the value of n
,
otherwise returns false
.
As with JavaScript, NaN
does not equal NaN
.
Note: This method uses the comparedTo
method internally.
0 === 1e-324 // true x = new BigNumber(0) x.equals('1e-324') // false BigNumber(-0).eq(x) // true ( -0 === 0 ) BigNumber(255).eq('ff', 16) // true y = new BigNumber(NaN) y.equals(NaN) // false
.floor() ⇒ BigNumber
Returns a BigNumber whose value is the value of this BigNumber rounded to a whole number in
the direction of negative Infinity
.
x = new BigNumber(1.8) x.floor() // '1' y = new BigNumber(-1.3) y.floor() // '-2'
.gt(n [, base]) ⇒ boolean
n
: number|string|BigNumber
base
: number
See BigNumber for further parameter details.
Returns true
if the value of this BigNumber is greater than the value of
n
, otherwise returns false
.
Note: This method uses the comparedTo
method internally.
0.1 > (0.3 - 0.2) // true x = new BigNumber(0.1) x.greaterThan(BigNumber(0.3).minus(0.2)) // false BigNumber(0).gt(x) // false BigNumber(11, 3).gt(11.1, 2) // true
.gte(n [, base]) ⇒ boolean
n
: number|string|BigNumber
base
: number
See BigNumber for further parameter details.
Returns true
if the value of this BigNumber is greater than or equal to the value
of n
, otherwise returns false
.
Note: This method uses the comparedTo
method internally.
(0.3 - 0.2) >= 0.1 // false x = new BigNumber(0.3).minus(0.2) x.greaterThanOrEqualTo(0.1) // true BigNumber(1).gte(x) // true BigNumber(10, 18).gte('i', 36) // true
.isFinite() ⇒ boolean
Returns true
if the value of this BigNumber is a finite number, otherwise
returns false
.
The only possible non-finite values of a BigNumber are NaN
, Infinity
and -Infinity
.
x = new BigNumber(1) x.isFinite() // true y = new BigNumber(Infinity) y.isFinite() // false
Note: The native method isFinite()
can be used if
n <= Number.MAX_VALUE
.
.isInt() ⇒ boolean
Returns true
if the value of this BigNumber is a whole number, otherwise returns
false
.
x = new BigNumber(1) x.isInteger() // true y = new BigNumber(123.456) y.isInt() // false
.isNaN() ⇒ boolean
Returns true
if the value of this BigNumber is NaN
, otherwise
returns false
.
x = new BigNumber(NaN) x.isNaN() // true y = new BigNumber('Infinity') y.isNaN() // false
Note: The native method isNaN()
can also be used.
.isNeg() ⇒ boolean
Returns true
if the value of this BigNumber is negative, otherwise returns
false
.
x = new BigNumber(-0) x.isNegative() // true y = new BigNumber(2) y.isNeg() // false
Note: n < 0
can be used if n <= -Number.MIN_VALUE
.
.isZero() ⇒ boolean
Returns true
if the value of this BigNumber is zero or minus zero, otherwise
returns false
.
x = new BigNumber(-0) x.isZero() && x.isNeg() // true y = new BigNumber(Infinity) y.isZero() // false
Note: n == 0
can be used if n >= Number.MIN_VALUE
.
.lt(n [, base]) ⇒ boolean
n
: number|string|BigNumber
base
: number
See BigNumber for further parameter details.
Returns true
if the value of this BigNumber is less than the value of
n
, otherwise returns false
.
Note: This method uses the comparedTo
method internally.
(0.3 - 0.2) < 0.1 // true x = new BigNumber(0.3).minus(0.2) x.lessThan(0.1) // false BigNumber(0).lt(x) // true BigNumber(11.1, 2).lt(11, 3) // true
.lte(n [, base]) ⇒ boolean
n
: number|string|BigNumber
base
: number
See BigNumber for further parameter details.
Returns true
if the value of this BigNumber is less than or equal to the value of
n
, otherwise returns false
.
Note: This method uses the comparedTo
method internally.
0.1 <= (0.3 - 0.2) // false x = new BigNumber(0.1) x.lessThanOrEqualTo(BigNumber(0.3).minus(0.2)) // true BigNumber(-1).lte(x) // true BigNumber(10, 18).lte('i', 36) // true
.minus(n [, base]) ⇒ BigNumber
n
: number|string|BigNumber
base
: number
See BigNumber for further parameter details.
Returns a BigNumber whose value is the value of this BigNumber minus n
.
The return value is always exact and unrounded.
0.3 - 0.1 // 0.19999999999999998 x = new BigNumber(0.3) x.minus(0.1) // '0.2' x.minus(0.6, 20) // '0'
.mod(n [, base]) ⇒ BigNumber
n
: number|string|BigNumber
base
: number
See BigNumber for further parameter details.
Returns a BigNumber whose value is the value of this BigNumber modulo n
, i.e.
the integer remainder of dividing this BigNumber by n
.
The value returned, and in particular its sign, is dependent on the value of the
MODULO_MODE
setting of this BigNumber constructor.
If it is 1
(default value), the result will have the same sign as this BigNumber,
and it will match that of Javascript's %
operator (within the limits of double
precision) and BigDecimal's remainder
method.
The return value is always exact and unrounded.
See MODULO_MODE
for a description of the other
modulo modes.
1 % 0.9 // 0.09999999999999998 x = new BigNumber(1) x.modulo(0.9) // '0.1' y = new BigNumber(33) y.mod('a', 33) // '3'
.neg() ⇒ BigNumber
Returns a BigNumber whose value is the value of this BigNumber negated, i.e. multiplied by
-1
.
x = new BigNumber(1.8) x.negated() // '-1.8' y = new BigNumber(-1.3) y.neg() // '1.3'
.plus(n [, base]) ⇒ BigNumber
n
: number|string|BigNumber
base
: number
See BigNumber for further parameter details.
Returns a BigNumber whose value is the value of this BigNumber plus n
.
The return value is always exact and unrounded.
0.1 + 0.2 // 0.30000000000000004 x = new BigNumber(0.1) y = x.plus(0.2) // '0.3' BigNumber(0.7).plus(x).plus(y) // '1' x.plus('0.1', 8) // '0.225'
.sd([z]) ⇒ number
z
: boolean|number: true
, false
, 0
or 1
Returns the number of significant digits of the value of this BigNumber.
If z
is true
or 1
then any trailing zeros of the
integer part of a number are counted as significant digits, otherwise they are not.
x = new BigNumber(1.234) x.precision() // 4 y = new BigNumber(987000) y.sd() // 3 y.sd(true) // 6
.round([dp [, rm]]) ⇒ BigNumber
dp
: number: integer, 0
to 1e+9
inclusive
rm
: number: integer, 0
to 8
inclusive
Returns a BigNumber whose value is the value of this BigNumber rounded by rounding mode
rm
to a maximum of dp
decimal places.
if dp
is omitted, or is null
or undefined
, the
return value is n
rounded to a whole number.
if rm
is omitted, or is null
or undefined
,
ROUNDING_MODE
is used.
See Errors for the treatment of other non-integer or out of range
dp
or rm
values.
x = 1234.56 Math.round(x) // 1235 y = new BigNumber(x) y.round() // '1235' y.round(1) // '1234.6' y.round(2) // '1234.56' y.round(10) // '1234.56' y.round(0, 1) // '1234' y.round(0, 6) // '1235' y.round(1, 1) // '1234.5' y.round(1, BigNumber.ROUND_HALF_EVEN) // '1234.6' y // '1234.56'
.shift(n) ⇒ BigNumber
n
: number: integer,
-9007199254740991
to 9007199254740991
inclusive
Returns a BigNumber whose value is the value of this BigNumber shifted n
places.
The shift is of the decimal point, i.e. of powers of ten, and is to the left if n
is negative or to the right if n
is positive.
The return value is always exact and unrounded.
x = new BigNumber(1.23) x.shift(3) // '1230' x.shift(-3) // '0.00123'
.sqrt() ⇒ BigNumber
Returns a BigNumber whose value is the square root of the value of this BigNumber,
rounded according to the current
DECIMAL_PLACES
and
ROUNDING_MODE
configuration.
The return value will be correctly rounded, i.e. rounded as if the result was first calculated to an infinite number of correct digits before rounding.
x = new BigNumber(16) x.squareRoot() // '4' y = new BigNumber(3) y.sqrt() // '1.73205080756887729353'
.times(n [, base]) ⇒ BigNumber
n
: number|string|BigNumber
base
: number
See BigNumber for further parameter details.
Returns a BigNumber whose value is the value of this BigNumber times n
.
The return value is always exact and unrounded.
0.6 * 3 // 1.7999999999999998 x = new BigNumber(0.6) y = x.times(3) // '1.8' BigNumber('7e+500').times(y) // '1.26e+501' x.times('-a', 16) // '-6'
.toDigits([sd [, rm]]) ⇒ BigNumber
sd
: number: integer, 1
to 1e+9
inclusive.
rm
: number: integer, 0
to 8
inclusive.
Returns a BigNumber whose value is the value of this BigNumber rounded to sd
significant digits using rounding mode rm
.
If sd
is omitted or is null
or undefined
, the return
value will not be rounded.
If rm
is omitted or is null
or undefined
,
ROUNDING_MODE
will be used.
See Errors for the treatment of other non-integer or out of range
sd
or rm
values.
BigNumber.config({ precision: 5, rounding: 4 }) x = new BigNumber(9876.54321) x.toDigits() // '9876.5' x.toDigits(6) // '9876.54' x.toDigits(6, BigNumber.ROUND_UP) // '9876.55' x.toDigits(2) // '9900' x.toDigits(2, 1) // '9800' x // '9876.54321'
.toExponential([dp [, rm]]) ⇒ string
dp
: number: integer, 0
to 1e+9
inclusive
rm
: number: integer, 0
to 8
inclusive
Returns a string representing the value of this BigNumber in exponential notation rounded
using rounding mode rm
to dp
decimal places, i.e with one digit
before the decimal point and dp
digits after it.
If the value of this BigNumber in exponential notation has fewer than dp
fraction
digits, the return value will be appended with zeros accordingly.
If dp
is omitted, or is null
or undefined
, the number
of digits after the decimal point defaults to the minimum number of digits necessary to
represent the value exactly.
If rm
is omitted or is null
or undefined
,
ROUNDING_MODE
is used.
See Errors for the treatment of other non-integer or out of range
dp
or rm
values.
x = 45.6 y = new BigNumber(x) x.toExponential() // '4.56e+1' y.toExponential() // '4.56e+1' x.toExponential(0) // '5e+1' y.toExponential(0) // '5e+1' x.toExponential(1) // '4.6e+1' y.toExponential(1) // '4.6e+1' y.toExponential(1, 1) // '4.5e+1' (ROUND_DOWN) x.toExponential(3) // '4.560e+1' y.toExponential(3) // '4.560e+1'
.toFixed([dp [, rm]]) ⇒ string
dp
: number: integer, 0
to 1e+9
inclusive
rm
: number: integer, 0
to 8
inclusive
Returns a string representing the value of this BigNumber in normal (fixed-point) notation
rounded to dp
decimal places using rounding mode rm
.
If the value of this BigNumber in normal notation has fewer than dp
fraction
digits, the return value will be appended with zeros accordingly.
Unlike Number.prototype.toFixed
, which returns exponential notation if a number
is greater or equal to 1021
, this method will always return normal
notation.
If dp
is omitted or is null
or undefined
, the return
value will be unrounded and in normal notation. This is also unlike
Number.prototype.toFixed
, which returns the value to zero decimal places.
It is useful when fixed-point notation is required and the current
EXPONENTIAL_AT
setting causes
toString
to return exponential notation.
If rm
is omitted or is null
or undefined
,
ROUNDING_MODE
is used.
See Errors for the treatment of other non-integer or out of range
dp
or rm
values.
x = 3.456 y = new BigNumber(x) x.toFixed() // '3' y.toFixed() // '3.456' y.toFixed(0) // '3' x.toFixed(2) // '3.46' y.toFixed(2) // '3.46' y.toFixed(2, 1) // '3.45' (ROUND_DOWN) x.toFixed(5) // '3.45600' y.toFixed(5) // '3.45600'
.toFormat([dp [, rm]]) ⇒ string
dp
: number: integer, 0
to 1e+9
inclusive
rm
: number: integer, 0
to 8
inclusive
Returns a string representing the value of this BigNumber in normal (fixed-point) notation
rounded to dp
decimal places using rounding mode rm
, and formatted
according to the properties of the FORMAT
object.
See the examples below for the properties of the
FORMAT
object, their types and their usage.
If dp
is omitted or is null
or undefined
, then the
return value is not rounded to a fixed number of decimal places.
If rm
is omitted or is null
or undefined
,
ROUNDING_MODE
is used.
See Errors for the treatment of other non-integer or out of range
dp
or rm
values.
format = { decimalSeparator: '.', groupSeparator: ',', groupSize: 3, secondaryGroupSize: 0, fractionGroupSeparator: ' ', fractionGroupSize: 0 } BigNumber.config({ FORMAT: format }) x = new BigNumber('123456789.123456789') x.toFormat() // '123,456,789.123456789' x.toFormat(1) // '123,456,789.1' // If a reference to the object assigned to FORMAT has been retained, // the format properties can be changed directly format.groupSeparator = ' ' format.fractionGroupSize = 5 x.toFormat() // '123 456 789.12345 6789' BigNumber.config({ FORMAT: { decimalSeparator: ',', groupSeparator: '.', groupSize: 3, secondaryGroupSize: 2 } }) x.toFormat(6) // '12.34.56.789,123'
.toFraction([max]) ⇒ [string, string]
max
: number|string|BigNumber: integer >= 1
and <
Infinity
Returns a string array representing the value of this BigNumber as a simple fraction with an
integer numerator and an integer denominator. The denominator will be a positive non-zero
value less than or equal to max
.
If a maximum denominator, max
, is not specified, or is null
or
undefined
, the denominator will be the lowest value necessary to represent the
number exactly.
See Errors for the treatment of other non-integer or out of range
max
values.
x = new BigNumber(1.75) x.toFraction() // '7, 4' pi = new BigNumber('3.14159265358') pi.toFraction() // '157079632679,50000000000' pi.toFraction(100000) // '312689, 99532' pi.toFraction(10000) // '355, 113' pi.toFraction(100) // '311, 99' pi.toFraction(10) // '22, 7' pi.toFraction(1) // '3, 1'
.toJSON() ⇒ string
As valueOf
.
x = new BigNumber('177.7e+457') y = new BigNumber(235.4325) z = new BigNumber('0.0098074') // Serialize an array of three BigNumbers str = JSON.stringify( [x, y, z] ) // "["1.777e+459","235.4325","0.0098074"]" // Return an array of three BigNumbers JSON.parse(str, function (key, val) { return key === '' ? val : new BigNumber(val) })
.toNumber() ⇒ number
Returns the value of this BigNumber as a JavaScript number primitive.
Type coercion with, for example, the unary plus operator will also work, except that a BigNumber with the value minus zero will be converted to positive zero.
x = new BigNumber(456.789) x.toNumber() // 456.789 +x // 456.789 y = new BigNumber('45987349857634085409857349856430985') y.toNumber() // 4.598734985763409e+34 z = new BigNumber(-0) 1 / +z // Infinity 1 / z.toNumber() // -Infinity
.pow(n [, m]) ⇒ BigNumber
n
: number: integer,
-9007199254740991
to 9007199254740991
inclusive
m
: number|string|BigNumber
Returns a BigNumber whose value is the value of this BigNumber raised to the power
n
, and optionally modulo a modulus m
.
If n
is negative the result is rounded according to the current
DECIMAL_PLACES
and
ROUNDING_MODE
configuration.
If n
is not an integer or is out of range:
If ERRORS
is true
a BigNumber Error is thrown,
else if n
is greater than 9007199254740991
, it is interpreted as
Infinity
;
else if n
is less than -9007199254740991
, it is interpreted as
-Infinity
;
else if n
is otherwise a number, it is truncated to an integer;
else it is interpreted as NaN
.
As the number of digits of the result of the power operation can grow so large so quickly,
e.g. 123.45610000 has over 50000
digits, the number of significant
digits calculated is limited to the value of the
POW_PRECISION
setting (unless a modulus
m
is specified).
By default POW_PRECISION
is set to 0
.
This means that an unlimited number of significant digits will be calculated, and that the
method's performance will decrease dramatically for larger exponents.
Negative exponents will be calculated to the number of decimal places specified by
DECIMAL_PLACES
(but not to more than
POW_PRECISION
significant digits).
If m
is specified and the value of m
, n
and this
BigNumber are positive integers, then a fast modular exponentiation algorithm is used,
otherwise if any of the values is not a positive integer the operation will simply be
performed as x.toPower(n).modulo(m)
with a
POW_PRECISION
of 0
.
Math.pow(0.7, 2) // 0.48999999999999994 x = new BigNumber(0.7) x.toPower(2) // '0.49' BigNumber(3).pow(-2) // '0.11111111111111111111'
.toPrecision([sd [, rm]]) ⇒ string
sd
: number: integer, 1
to 1e+9
inclusive
rm
: number: integer, 0
to 8
inclusive
Returns a string representing the value of this BigNumber rounded to sd
significant digits using rounding mode rm
.
If sd
is less than the number of digits necessary to represent the integer part
of the value in normal (fixed-point) notation, then exponential notation is used.
If sd
is omitted, or is null
or undefined
, then the
return value is the same as n.toString()
.
If rm
is omitted or is null
or undefined
,
ROUNDING_MODE
is used.
See Errors for the treatment of other non-integer or out of range
sd
or rm
values.
x = 45.6 y = new BigNumber(x) x.toPrecision() // '45.6' y.toPrecision() // '45.6' x.toPrecision(1) // '5e+1' y.toPrecision(1) // '5e+1' y.toPrecision(2, 0) // '4.6e+1' (ROUND_UP) y.toPrecision(2, 1) // '4.5e+1' (ROUND_DOWN) x.toPrecision(5) // '45.600' y.toPrecision(5) // '45.600'
.toString([base]) ⇒ string
base
: number: integer, 2
to 64
inclusive
Returns a string representing the value of this BigNumber in the specified base, or base
10
if base
is omitted or is null
or
undefined
.
For bases above 10
, values from 10
to 35
are
represented by a-z
(as with Number.prototype.toString
),
36
to 61
by A-Z
, and 62
and
63
by $
and _
respectively.
If a base is specified the value is rounded according to the current
DECIMAL_PLACES
and ROUNDING_MODE
configuration.
If a base is not specified, and this BigNumber has a positive
exponent that is equal to or greater than the positive component of the
current EXPONENTIAL_AT
setting,
or a negative exponent equal to or less than the negative component of the
setting, then exponential notation is returned.
If base
is null
or undefined
it is ignored.
See Errors for the treatment of other non-integer or out of range
base
values.
x = new BigNumber(750000) x.toString() // '750000' BigNumber.config({ EXPONENTIAL_AT: 5 }) x.toString() // '7.5e+5' y = new BigNumber(362.875) y.toString(2) // '101101010.111' y.toString(9) // '442.77777777777777777778' y.toString(32) // 'ba.s' BigNumber.config({ DECIMAL_PLACES: 4 }); z = new BigNumber('1.23456789') z.toString() // '1.23456789' z.toString(10) // '1.2346'
.trunc() ⇒ BigNumber
Returns a BigNumber whose value is the value of this BigNumber truncated to a whole number.
x = new BigNumber(123.456) x.truncated() // '123' y = new BigNumber(-12.3) y.trunc() // '-12'
.valueOf() ⇒ string
As toString
, but does not accept a base argument and includes the minus sign
for negative zero.
x = new BigNumber('-0') x.toString() // '0' x.valueOf() // '-0' y = new BigNumber('1.777e+457') y.valueOf() // '1.777e+457'
The properties of a BigNumber instance:
Property | Description | Type | Value |
---|---|---|---|
c | coefficient* | number[] |
Array of base 1e14 numbers |
e | exponent | number | Integer, -1000000000 to 1000000000 inclusive |
s | sign | number | -1 or 1 |
isBigNumber | type identifier | boolean | true |
*significand
The value of any of the c
, e
and s
properties may also
be null
.
From v2.0.0 of this library, the value of the coefficient of a BigNumber is stored in a
normalised base 100000000000000
floating point format, as opposed to the base
10
format used in v1.x.x
This change means the properties of a BigNumber are now best considered to be read-only. Previously it was acceptable to change the exponent of a BigNumber by writing to its exponent property directly, but this is no longer recommended as the number of digits in the first element of the coefficient array is dependent on the exponent, so the coefficient would also need to be altered.
Note that, as with JavaScript numbers, the original exponent and fractional trailing zeros are not necessarily preserved.
x = new BigNumber(0.123) // '0.123' x.toExponential() // '1.23e-1' x.c // '1,2,3' x.e // -1 x.s // 1 y = new Number(-123.4567000e+2) // '-12345.67' y.toExponential() // '-1.234567e+4' z = new BigNumber('-123.4567000e+2') // '-12345.67' z.toExponential() // '-1.234567e+4' z.c // '1,2,3,4,5,6,7' z.e // 4 z.s // -1
Checking if a value is a BigNumber instance:
x = new BigNumber(3) x instanceof BigNumber // true x.isBigNumber // true BN = BigNumber.another(); y = new BN(3) y instanceof BigNumber // false y.isBigNumber // true
The table below shows how ±0
, NaN
and
±Infinity
are stored.
c | e | s | |
---|---|---|---|
±0 | [0] |
0 |
±1 |
NaN | null |
null |
null |
±Infinity | null |
null |
±1 |
x = new Number(-0) // 0 1 / x == -Infinity // true y = new BigNumber(-0) // '0' y.c // '0' ( [0].toString() ) y.e // 0 y.s // -1
The errors that are thrown are generic Error
objects with name
BigNumber Error.
The table below shows the errors that may be thrown if ERRORS
is
true
, and the action taken if ERRORS
is false
.
Method(s) | ERRORS: true Throw BigNumber Error |
ERRORS: false Action on invalid argument |
---|---|---|
BigNumber |
number type has more than 15 significant digits |
Accept. |
not a base... number | Substitute NaN . |
|
base not an integer | Truncate to integer. Ignore if not a number. |
|
base out of range | Ignore. | |
not a number* | Substitute NaN . |
|
another |
not an object | Ignore. |
config |
DECIMAL_PLACES not an integer |
Truncate to integer. Ignore if not a number. |
DECIMAL_PLACES out of range |
Ignore. | |
ROUNDING_MODE not an integer |
Truncate to integer. Ignore if not a number. |
|
ROUNDING_MODE out of range |
Ignore. | |
EXPONENTIAL_AT not an integeror not [integer, integer] |
Truncate to integer(s). Ignore if not number(s). |
|
EXPONENTIAL_AT out of rangeor not [negative, positive] |
Ignore. | |
RANGE not an integeror not [integer, integer] |
Truncate to integer(s). Ignore if not number(s). |
|
RANGE cannot be zero |
Ignore. | |
RANGE out of rangeor not [negative, positive] |
Ignore. | |
ERRORS not a booleanor binary digit |
Ignore. | |
CRYPTO not a booleanor binary digit |
Ignore. | |
CRYPTO crypto unavailable |
Ignore. | |
MODULO_MODE not an integer |
Truncate to integer. Ignore if not a number. |
|
MODULO_MODE out of range |
Ignore. | |
POW_PRECISION not an integer |
Truncate to integer. Ignore if not a number. |
|
POW_PRECISION out of range |
Ignore. | |
FORMAT not an object |
Ignore. | |
precision |
argument not a boolean or binary digit |
Ignore. |
round |
decimal places not an integer | Truncate to integer. Ignore if not a number. |
decimal places out of range | Ignore. | |
rounding mode not an integer | Truncate to integer. Ignore if not a number. |
|
rounding mode out of range | Ignore. | |
shift |
argument not an integer | Truncate to integer. Ignore if not a number. |
argument out of range | Substitute ±Infinity .
| |
toExponential toFixed toFormat
|
decimal places not an integer | Truncate to integer. Ignore if not a number. |
decimal places out of range | Ignore. | |
rounding mode not an integer | Truncate to integer. Ignore if not a number. |
|
rounding mode out of range | Ignore. | |
toFraction |
max denominator not an integer | Truncate to integer. Ignore if not a number. |
max denominator out of range | Ignore. | |
toDigits toPrecision
|
precision not an integer | Truncate to integer. Ignore if not a number. |
precision out of range | Ignore. | |
rounding mode not an integer | Truncate to integer. Ignore if not a number. |
|
rounding mode out of range | Ignore. | |
toPower |
exponent not an integer | Truncate to integer. Substitute NaN if not a number. |
exponent out of range | Substitute ±Infinity .
|
|
toString |
base not an integer | Truncate to integer. Ignore if not a number. |
base out of range | Ignore. |
*No error is thrown if the value is NaN
or 'NaN'.
The message of a BigNumber Error will also contain the name of the method from which the error originated.
To determine if an exception is a BigNumber Error:
try { // ... } catch (e) { if ( e instanceof Error && e.name == 'BigNumber Error' ) { // ... } }
Some arbitrary-precision libraries retain trailing fractional zeros as they can indicate the precision of a value. This can be useful but the results of arithmetic operations can be misleading.
x = new BigDecimal("1.0") y = new BigDecimal("1.1000") z = x.add(y) // 2.1000 x = new BigDecimal("1.20") y = new BigDecimal("3.45000") z = x.multiply(y) // 4.1400000
To specify the precision of a value is to specify that the value lies within a certain range.
In the first example, x
has a value of 1.0
. The trailing zero shows
the precision of the value, implying that it is in the range 0.95
to
1.05
. Similarly, the precision indicated by the trailing zeros of y
indicates that the value is in the range 1.09995
to 1.10005
.
If we add the two lowest values in the ranges we have, 0.95 + 1.09995 = 2.04995
,
and if we add the two highest values we have, 1.05 + 1.10005 = 2.15005
, so the
range of the result of the addition implied by the precision of its operands is
2.04995
to 2.15005
.
The result given by BigDecimal of 2.1000
however, indicates that the value is in
the range 2.09995
to 2.10005
and therefore the precision implied by
its trailing zeros may be misleading.
In the second example, the true range is 4.122744
to 4.157256
yet
the BigDecimal answer of 4.1400000
indicates a range of 4.13999995
to 4.14000005
. Again, the precision implied by the trailing zeros may be
misleading.
This library, like binary floating point and most calculators, does not retain trailing
fractional zeros. Instead, the toExponential
, toFixed
and
toPrecision
methods enable trailing zeros to be added if and when required.