Then call `rollup` either via the [CLI](https://www.rollupjs.org/guide/en/#command-line-reference) or the [API](https://www.rollupjs.org/guide/en/#javascript-api).
The configuration above will replace every instance of `process.env.NODE_ENV` with `"production"` and `__buildDate__` with the result of the given function in any file included in the build.
_Note: Values must be either primitives (e.g. string, number) or `function` that returns a string. For complex values, use `JSON.stringify`. To replace a target with a value that will be evaluated as a string, set the value to a quoted string (e.g. `"test"`) or use `JSON.stringify` to preprocess the target string safely._
Typically, `@rollup/plugin-replace` should be placed in `plugins`_before_ other plugins so that they may apply optimizations, such as dead code removal.
## Options
In addition to the properties and values specified for replacement, users may also specify the options below.
### `delimiters`
Type: `Array[...String, String]`<br>
Default: `['\b', '\b']`
Specifies the boundaries around which strings will be replaced. By default, delimiters are [word boundaries](https://www.regular-expressions.info/wordboundaries.html). See [Word Boundaries](#word-boundaries) below for more information.
### `preventAssignment`
Type: `Boolean`<br>
Default: `false`
Prevents replacing strings where they are followed by a single equals sign. For example, where the plugin is called as follows:
```js
replace({
values: {
'process.env.DEBUG': 'false'
}
});
```
Observe the following code:
```js
// Input
process.env.DEBUG = false;
if (process.env.DEBUG == true) {
//
}
// Without `preventAssignment`
false = false; // this throws an error because false cannot be assigned to
if (false == true) {
//
}
// With `preventAssignment`
process.env.DEBUG = false;
if (false == true) {
//
}
```
### `exclude`
Type: `String` | `Array[...String]`<br>
Default: `null`
A [minimatch pattern](https://github.com/isaacs/minimatch), or array of patterns, which specifies the files in the build the plugin should _ignore_. By default no files are ignored.
### `include`
Type: `String` | `Array[...String]`<br>
Default: `null`
A [minimatch pattern](https://github.com/isaacs/minimatch), or array of patterns, which specifies the files in the build the plugin should operate on. By default all files are targeted.
### `values`
Type: `{ [key: String]: Replacement }`, where `Replacement` is either a string or a `function` that returns a string.
Default: `{}`
To avoid mixing replacement strings with the other options, you can specify replacements in the `values` option. For example, the following signature:
```js
replace({
include: ['src/**/*.js'],
changed: 'replaced'
});
```
Can be replaced with:
```js
replace({
include: ['src/**/*.js'],
values: {
changed: 'replaced'
}
});
```
## Word Boundaries
By default, values will only match if they are surrounded by _word boundaries_.
Consider the following options and build file:
```js
module.exports = {
...
plugins: [replace({ changed: 'replaced' })]
};
```
```js
// file.js
console.log('changed');
console.log('unchanged');
```
The result would be:
```js
// file.js
console.log('replaced');
console.log('unchanged');
```
To ignore word boundaries and replace every instance of the string, wherever it may be, specify empty strings as delimiters:
