One of the most common use cases of task pipelines is doing something with several files.
RxLine comes with utility functions in rxline/fs to make that super convenient.
Assume we have the following file structure:
1./
2-| bavaria/
3-|-------| munich/
4-|-------|-------| index.js
5-|-------|-------| schwabing.js
6-|-------| garching.js
7-|-------| augsburg.ts
8-| index.js
9-| berlin.js
You can get all files like this:
1import { files } from 'rxline/fs';
2
3files('.')
4 .peek(f => console.log(f.path))
5 .process();
6
7// Result:
8// > index.js
9// > berlin.js
10// > bavaria/augsburg.ts
11// > bavaria/garching.js
12// > bavaria/munich/index.js
13// > bavaria/munich/schwabing.js
files() creates a line with File objects representing all files in given address.
You can turn off the recursive scan:
1files('.', { recursive: false })
2 .peek(f => console.log(f.path))
3 .process();
4
5// Result:
6// > index.js
7// > berlin.js
You can change scan root:
1files('.', { root: 'bavaria' })
2 .peek(f => console.log(f.path))
3 .process();
4
5// Result:
6// > garching.js
7// > augsburg.ts
8// > munich/index.js
9// > munich/schwabing.js
Or specify search directory:
1files('munich', { root: 'bavaria' })
2 .peek(f => console.log(f.path))
3 .process();
4
5// Result:
6// > munich/index.js
7// > munich/schwabing.js
1import { files, pathMatch } from 'rxline/fs';
2
3files('bavaria') // --> scan files in `bavaria`
4 .pick(pathMatch(/\.js$/)) // --> pick those with `.js` extension
5 .peek(f => console.log(f.path))
6 .process();
7
8// Result:
9// > bavaria/garching.js
10// > bavaria/munich/index.js
11// > bavaria/munich/schwabing.js
1files('.')
2 .drop(pathMatch(/\/munich\//)) // --> drop files in `munich` folder
3 .peek(f => console.log(f.path))
4 .process();
5
6// Result:
7// > index.js
8// > berlin.js
9// > bavaria/garching.js
10// > bavaria/augsburg.ts
By default, the content of the files are not loaded:
1files('munich', { root: 'bavaria')
2 .peek(f => console.log(f.path + ' : ' + f.content))
3 .process();
4
5// Result:
6// > munich/index.js : undefined
7// > munich/schwabing.js : undefined
You can load file contents using readFile():
1import { files, readFile } from 'rxline/fs';
2
3files('munich', { root: 'bavaria')
4 .pipe(readFile())
5 .peek(f => console.log(f.path + ' : ' + f.content.split('\n').length + ' lines'))
6 .process();
7
8// Result:
9// > munich/index.js : 56 lines
10// > munich/schwabing.js : 215 lines
You can use mapContent() to modify file contents, and writeFile() to save the files:
1import { concurrently } from 'rxline';
2import { files, pathMatch, readFile, writeFile, mapContent } from 'rxline/fs';
3
4files('.', { root: 'bavaria' }) // --> all files with root: `bavaria/`
5 .pick(pathMatch(/\.js$/)) // --> pick `.js` files
6 .pipe(readFile(), // --> read'em
7 mapContent(
8 (content, path) => `/** file: ${path} **/\n` + content // --> modify the content (in memory)
9 ),
10 writeFile()) // --> save them
11 .process(concurrently); // --> all in parallel.
12
13// Adds first line `/** file: garching.js **/` to `bavaria/garching.js`
14// Adds first line `/** file: munich/index.js **/ to `bavaria/munich/index.js`
15// Adds first line `/** file: munich/schwabing.js **/ to `bavaria/munich/schwabing.js`
mapPath() modifies each file's path:
1import { files, readFile, writeFile, mapPath, pathMatch } from 'rxline/fs';
2
3files('.')
4 .drop(pathMatch(/\.js$/)) // --> drop all `.js` files
5 .pipe(readFile(), // --> read the rest
6 mapPath(path => path + '.bak'), // --> add `.bak` to their path
7 writeFile()) // --> save them.
8 .process();
9
10// Creates `bavaria/augsburg.ts.bak`, a copy of `bavaria/augsburg.ts`.
mapExt() modifies each file's extension:
1import { files, readFile, writeFile, mapExt } from 'rxline/fs';
2
3files('.', { root : 'bavaria' })
4 .pipe(readFile(), // --> read the files
5 mapExt(ext => 'bak' + ext), // --> suffix `bak` to their extension
6 writeFile()) // --> save them.
7 .process();
8
9// Creates `bavaria/augsburg.bak.ts`, a copy of `bavaria/augsburg.ts`.
10// Creates `bavaria/garching.bak.js`, a copy of `bavaria/garching.js`.
11// Creates `bavaria/munich/index.bak.js`, a copy of `bavaria/munich/index.js`.
12// Creates `bavaria/munich/schwabing.bak.js`, a copy of `bavaria/munich/schwabing.js`.
mapRoot() modifies the root folder (so you can easily move files somewhere else):
1import { files, readFile, writeFile, mapExt, mapRoot } from 'rxline/fs';
2
3files('munich', { root : 'bavaria' })
4 .pipe(readFile(), // --> read the files
5 mapRoot(() => 'backup'), // --> change their root to `backup/`
6 writeFile()) // --> save them.
7 .process();
8
9// Creates `backup/munich/index.js`, a copy of `bavaria/munich/index.js`.
10// Creates `backup/munich/schwabing.js`, a copy of `bavaria/munich/schwabing.js`.