antfu / magic-string-extra

Extended magic-string with extra utilities

DEPRECATED. It has been ported back to magic-string >= 0.26.0

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magic-string-extra

Extended Rich-Harris/magic-string with extra utilities.

Install

npm i magic-string-extra

magic-string-extra can be a drop-in replacement for magic-string:

- import MagicString from 'magic-string'
+ import MagicString from 'magic-string-extra'

Extra Utils

Check magic-string's documentation for the base utils.

.replace()

Shares the same signature as String.prototype.replace. Supports RegExp and replacer functions.

import MagicString from 'magic-string-extra'

const s = new MagicString(source)

s.replace(foo, 'bar')
s.replace(/foo/g, 'bar')
s.replace(/(\w)(\d+)/g, (_, $1, $2) => $1.toUpperCase() + $2)

The differences from String.replace:

• It will always match against the original string
• It mutates the magic string state (use .clone() to be immutable)

.hasChanged()

In some cases, when the string does not change you might be able to skip the sourcemap generation to improve the performance (e.g. Rollup and Vite's transform hook). This function allows you to check the state without tracking it externally.

import MagicString from 'magic-string-extra'

const s = new MagicString(source)

s.hasChanged() // false

s.prepend('foo')

s.hasChanged() // true

.toRollupResult()

It's common to use the magic string for code transformations in plugins. This function provides a shorthand to generate the result in Rollup's TransformResult format. When the string has not changed, null will be returned to skip the Rollup transformation.

import MagicString from 'magic-string-extra'

const s = new MagicString(source)

s.toRollupResult() // { code, map } | null

Included Upstream PRs

• #183 - fix(types): mark MagicString options as optional
• #179 - docs: add TSDoc

Sponsors

License

MIT License © 2022 Anthony Fu