hexo/node_modules/es-abstract/helpers/getIteratorMethod.js

48 lines
1.2 KiB
JavaScript

'use strict';
var hasSymbols = require('has-symbols')();
var GetIntrinsic = require('get-intrinsic');
var callBound = require('call-bind/callBound');
var isString = require('is-string');
var $iterator = GetIntrinsic('%Symbol.iterator%', true);
var $stringSlice = callBound('String.prototype.slice');
var $String = GetIntrinsic('%String%');
module.exports = function getIteratorMethod(ES, iterable) {
var usingIterator;
if (hasSymbols) {
usingIterator = ES.GetMethod(iterable, $iterator);
} else if (ES.IsArray(iterable)) {
usingIterator = function () {
var i = -1;
var arr = this; // eslint-disable-line no-invalid-this
return {
next: function () {
i += 1;
return {
done: i >= arr.length,
value: arr[i]
};
}
};
};
} else if (isString(iterable)) {
usingIterator = function () {
var i = 0;
return {
next: function () {
var nextIndex = ES.AdvanceStringIndex($String(iterable), i, true);
var value = $stringSlice(iterable, i, nextIndex);
i = nextIndex;
return {
done: nextIndex > iterable.length,
value: value
};
}
};
};
}
return usingIterator;
};