@frsource/frs-replace - replace content directly in your files/streams with ease (CLI included)! 📝

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The fastest (see benchmarks) CLI & Node wrapper around javascript replace which allows in-file replacing (with possibility to save changed file as a copy), globbing, piping and many more!

Getting Started (CLI)
·
Examples and recipes (CLI)


Getting Started (Node)
·
Examples and recipes (Node)

:scroll: Installation

``bash
npm install @frsource/frs-replace
`

or execute it right away:

`bash
npx @frsource/frs-replace
`

:keyboard: CLI

`bash
frs-replace [flags]
`

Basic usage:

`bash
frs-replace something anything -i foo.js -o foo_replaced.js

all of the occurences of "something" in foo.js will be replaced with "anything" and saved to foo_replaced.js


`

More examples below.

$3

| Argument | Type | Description |
| --------------- | ------ | --------------------------------------------------------------------------------------------------------------------------------------- |
| \ | string | First parameter to RegExp constructor |
| \ | string | String or path to replacement function file (see ‑‑replace‑fn switch for details) |

$3

> Note: Every boolean option can be negated with use of --no- prefix, e.g. --stdout or --no-stdout turn stdout output on or off, respectively.

> Note: Object types can be set using dot notation. So, e.g. if you want to pass utf8 value under i-read-opts encoding field you should write --i-read-opts.encoding utf8.

| Option | Type | Default | Description |
| ---------------------------------------- | ------------------------------------------- | ------------------------------------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| ‑i, ‑‑input | string or string[] | _-_ | Path to files or fast-glob pattern pointing to files to be read & replaced from. If multiple files specified results will be joined using outputJoinString option's value) |
| ‑‑i-read-opts | string or object | utf8 | Options which are passed directly to the readFileSync method when reading input file |
| ‑‑i-glob-opts | object | _undefined_ | Options which are passed directly to the fast-glob package when resolving glob patterns |
| ‑‑stdin | boolean | _true_ | Wait for stdin input (should be set to _false_ when used in non-interactive terminals) |
| ‑o, ‑‑output | string | _-_ | Output file name/path (replaces the file if it already exists and creates any intermediate directories if they don't already exist) |
| ‑‑o-write-opts | string or object | utf8 | Passed as options argument of write's .sync |
| ‑‑o-join-str | string | \n | Used when joining multiple files, passed directly to javascript join |
| ‑c, ‑‑content | string | _-_ | Content to be replaced (takes precedence over stream & file input) |
| ‑s, ‑‑strategy | "join" or "flatten" or "preserve-structure" | "join" | Output file generation strategy. _"join"_ - joins all input files and outputs them as a single file using path passed as: _"output"_. _"preserve-structure"_ - saves all files to the _"output"_ directory keeping relative directory structure._"flatten"_ - same as _"preserve-structure"_ but flattens the directory structure |
| ‑f, ‑‑flags | string, combination of _gim_ flags | g | RegExp flags |
| ‑‑stdout | boolean | _true_ if piped input present, _false_ otherwise | Force sending output on stdout |
| ‑r, ‑‑replace‑fn | boolean | false | Treat replacement argument as path to file containing replacement function |
| ‑h, ‑‑help | boolean | _-_ | Show help |
| ‑v, ‑‑version | boolean | _-_ | Show version number |

:mag_right: Examples and recipes - CLI

##### 1. Replace all a occurrences with b from the foo.js file and return the result (using CLI)

`bash
frs-replace a b -i foo.js --stdout
`

##### 2. Replace all a occurrences with b from foo.js and save the result to the foo_replaced.js (using CLI)

`bash
frs-replace a b -i foo.js -o foo_replaced.js
`

##### 3. Replace all a occurrences with b from an array of files and save the result to the foo_replaced.js using default \n as a result-joining string (using CLI)

`bash
frs-replace a b -i foo.js -i foo2.js -o foo_replaced.js
`

##### 4. Replace all a occurrences with b from all .js files in the foo directory and save the result to the foo_replaced.js using \n/////\n as a result-joining string (using CLI)

`bash
frs-replace a b -i foo/*.js -o foo_replaced.js --o-join-str "\n/////\n"
`

##### 5. Replace all a occurrences with b in a content string abcd and save the result to the foo_replaced.js (using CLI)

`bash
frs-replace a b --content abcd -o foo_replaced.js
`

##### 6. Replace all a occurrences with b from a piped stream and save it to the output file (using CLI)

`bash
| frs-replace a b >
`

##### 7. Replace all a occurrences with b from a piped stream and pass it through the stdout stream to the (using CLI)

`bash
| frs-replace a b |
`

:books: Node API

@frsource/frs-replace package is shipped in 2 flavors: synchronous and asynchronous:

`javascript
import { sync, async } from '@frsource/frs-replace';

sync({
/ options /
});
await async({
/ options /
});
`

Where / options / is an object containing:

> Note: one of parameters: input or content is required

| Option | Type | Default | Description |
| ------------------ | ------------------------------------------------------------------------------------------------------------------------- | ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| input | string or string[] | _undefined_ | Path to files or fast-glob pattern pointing to files to be read & replaced from. If multiple files specified results will be joined using outputJoinString option's value) |
| inputReadOptions | string or object | utf8 | Options which are passed directly to the readFileSync method when reading input file |
| inputGlobOptions | object | _undefined_ | Options which are passed directly to the fast-glob package when resolving glob patterns |
| content | string | _undefined_ | Content to be replaced (takes precedence over file input) |
| strategy | "join" or "flatten" or "preserve-structure" | "join" | Output file generation strategy. _"join"_ - joins all input files and outputs them as a single file using path passed as: _"output"_. _"preserve-structure"_ - saves all files to the _"output"_ directory keeping relative directory structure._"flatten"_ - same as _"preserve-structure"_ but flattens the directory structure |
| needle | string or RegExp Object | _-_ | Used as a first argument of javascript replace |
| replacement | string | _-_ | Passed as a second argument to javascript replace |
| output | string | _undefined_ | Path of an output file |
| outputWriteOptions | string or object | "utf8" | Passed as options argument of write's .sync |
| outputJoinString | string | \n | String used when joining multiple files, passed directly to javascript join |

:mag_right: Examples and recipes - Node

> Note: While all of examples are using synchronous API method in all cases your can use async as well.

##### 1. Replace all a occurrences with b from the foo.js file and return the result

`javascript
import { sync } from '@frsource/frs-replace';

const result = sync({
input: 'foo.js',
regex: new RegExp('a', 'g'),
replacement: 'b',
output: 'foo_replaced.js',
});
`

##### 2. Replace all a occurrences with b from foo.js and save the result to the foo_replaced.js

`javascript
import { sync } from '@frsource/frs-replace';
const result = sync({
input: 'foo.js',
regex: new RegExp('a', 'g'),
replacement: 'b',
output: 'foo_replaced.js',
});
`

##### 3. Replace all a occurrences with b from an array of files and save the result to the foo_replaced.js using default \n as a result-joining string

`javascript
import { sync } from '@frsource/frs-replace';
const result = sync({
input: ['foo.js', 'foo2.js'],
regex: new RegExp('a', 'g'),
replacement: 'b',
output: 'foo_replaced.js',
});
`

##### 4. Replace all a occurrences with b from all .js files in the foo directory and save the result to the foo_replaced.js using \n/////\n as a result-joining string

`javascript
import { sync } from '@frsource/frs-replace';
const result = sync({
input: 'foo/*.js',
regex: new RegExp('a', 'g'),
replacement: 'b',
outputJoinString: '\n/////\n',
output: 'foo_replaced.js',
});
`

##### 5. Replace all a occurrences with b in a content string abcd and save the result to the foo_replaced.js

`javascript
import { sync } from '@frsource/frs-replace';
const result = sync({
content: 'abcd',
regex: new RegExp('a', 'g'),
replacement: 'b',
output: 'foo_replaced.js',
});
``

:chart_with_upwards_trend: Benchmarks

> Tested on Node v24.11.1.

$3

| Rank | Library | Average latency [ms] | Difference percentage (comparing to best average latency) |
| ---- | ----------------------------- | -------------------- | ----------------------------------------------------------------------------- |
| 1 | @frsource/frs-replace (sync) | 0.35 ± 0.98% | +0.00% |
| 2 | replace-in-file (sync) | 0.42 ± 2.14% | +19.77% |
| 3 | @frsource/frs-replace (async) | 1.65 ± 1.81% | +366.40% |
| 4 | replace-in-file (async) | 2.52 ± 1.39% | +613.32% |

$3

| Rank | Library | Average latency [ms] | Difference percentage (comparing to best average latency) |
| ---- | ----------------------------- | -------------------- | ----------------------------------------------------------------------------- |
| 1 | @frsource/frs-replace (sync) | 0.00 ± 0.62% | +0.00% |
| 2 | replaceString | 0.00 ± 0.39% | +21.58% |
| 3 | @frsource/frs-replace (async) | 0.00 ± 0.65% | +29.55% |