$ npm install @rollup/plugin-replace
🍣 A Rollup plugin which replaces targeted strings in files while bundling.
This plugin requires an LTS Node version (v14.0.0+) and Rollup v1.20.0+.
Using npm:
npm install @rollup/plugin-replace --save-dev
Create a rollup.config.js
configuration file and import the plugin:
import replace from '@rollup/plugin-replace';
export default {
input: 'src/index.js',
output: {
dir: 'output',
format: 'cjs'
},
plugins: [
replace({
'process.env.NODE_ENV': JSON.stringify('production'),
__buildDate__: () => JSON.stringify(new Date()),
__buildVersion: 15
})
]
};
Then call rollup
either via the CLI or the 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.
In addition to the properties and values specified for replacement, users may also specify the options below.
delimiters
Type: Array[String, String]
Default: ['\\b', '\\b(?!\\.)']
Specifies the boundaries around which strings will be replaced. By default, delimiters are word boundaries and also prevent replacements of instances with nested access. See Word Boundaries below for more information.
For example, if you pass typeof window
in values
to-be-replaced, then you could expect the following scenarios:
typeof window
will be replacedtypeof window.document
will not be replaced due to (?!\.)
boundarytypeof windowSmth
will not be replaced due to a \b
boundaryDelimiters will be used to build a Regexp
. To match special characters (any of .*+?^${}()|[]\
), be sure to escape them.
objectGuards
Type: Boolean
Default: false
When replacing dot-separated object properties like process.env.NODE_ENV
, will also replace typeof process
object guard
checks against the objects with the string "object"
.
For example:
replace({
values: {
'process.env.NODE_ENV': '"production"'
}
});
// Input
if (typeof process !== 'undefined' && process.env.NODE_ENV === 'production') {
console.log('production');
}
// Without `objectGuards`
if (typeof process !== 'undefined' && 'production' === 'production') {
console.log('production');
}
// With `objectGuards`
if ('object' !== 'undefined' && 'production' === 'production') {
console.log('production');
}
preventAssignment
Type: Boolean
Default: false
Prevents replacing strings where they are followed by a single equals sign. For example, where the plugin is called as follows:
replace({
values: {
'process.env.DEBUG': 'false'
}
});
Observe the following code:
// 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]
Default: null
A picomatch pattern, 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]
Default: null
A picomatch pattern, or array of patterns, which specifies the files in the build the plugin should operate on. By default all files are targeted.
sourceMap
or sourcemap
Type: Boolean
Default: false
Enables generating sourcemaps for the bundled code. For example, where the plugin is called as follows:
replace({
sourcemap: true
});
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:
replace({
include: ['src/**/*.js'],
changed: 'replaced'
});
Can be replaced with:
replace({
include: ['src/**/*.js'],
values: {
changed: 'replaced'
}
});
By default, values will only match if they are surrounded by word boundaries.
Consider the following options and build file:
module.exports = {
...
plugins: [replace({ changed: 'replaced' })]
};
// file.js
console.log('changed');
console.log('unchanged');
The result would be:
// 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:
export default {
...
plugins: [
replace({
changed: 'replaced',
delimiters: ['', '']
})
]
};
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