gulp-custom-filter

A gulp plugin to filter files by customized filters.

Install

$ npm install --save-dev gulp-custom-filter

Usage

var filter = require('gulp-custom-filter');
var gulp = require('gulp');
var less = require('gulp-less');
 
function myFilter(file) {
    return file.basename.startsWith('my_');
}
 
gulp.task('less', function() {
    return gulp.src('./less/**/*.less')
        .pipe(filter(myFilter))
        .pipe(less())
        .pipe(gulp.dest('./css')
});

This is equivalent to:

var filter = require('gulp-custom-filter');
var gulp = require('gulp');
var less = require('gulp-less');
 
gulp.task('less', function() {
    return gulp.src('./less/**/my_*.less')
        .pipe(less())
        .pipe(gulp.dest('./css')
});

You may set any predicate function to a vinyl file.

Basic filters

filter.not(fn)

Nagates filter conditions

var not = filter.not;
 
gulp.src('./less/**/*.less')
    .pipe(filter(not(myFilter)) // will pass files which not satisfy myFilter

This filter passes less files which its name does not start with 'my_'.

filter.and(fn1, fn2, ...)

Passes files which satisfy every filter conditions.

var and = filter.and;
 
gulp.src('./less/**/*.less')
    .pipe(filter(and(myFilter1, myFilter2)) // will pass files which satisfy myFilter1 and myFilter2

filter.or(fn1, fn2, ...)

Passes files which satisfy at least one of the filter conditions.

var or = filter.or;
 
gulp.src('./less/**/*.less')
    .pipe(filter(or(myFilter1, myFilter2)) // will pass files which satisfy myFilter1 or myFilter2

filter.all()

Passes every files. This is equivalent function() { return true; }

var all = filter.all;
 
gulp.src('./less/**/*.less')
    .pipe(filter(all())) // no file will be filtered out.

filter.none()

Passes no file. This is equivalent function() { return false; }

var none = filter.none;
 
gulp.src('./less/**/*.less')
    .pipe(filter(none())) // no file will be passed.

Filename pattern filters

filter.glob(pattern, options)

Glob pattern filter for file name. Just a wrapper of minimatch.

var glob = filter.glob;
 
gulp.src('./**/*.*')
    .pipe(filter(glob('./**/*.less'))).

pattern: a string or an array of glob pattern.
options: optional options.

filter.ignore(filename)

Ignore list filter.

var ignore = filter.ignore;
 
gulp.src('./**/*.*')
    .pipe(filter(ignore('.gitignore')))

filename: filename to ignore file.

Filter development guide

gulp-custom-filter accepts three type of predicate functions.

Simple boolean predicates: function(file, [encode]): boolean

A predicate must have one or two argument(s). It returns a boolean value true/false.

gulp.src('./**/*.*')
    .pipe(filter(function(file, encode) {
        return file.isBuffer();
    });

To fail the predicate, just throw an error.

gulp.src('./**/*.*')
    .pipe(filter(function(file, encode) {
        throw new Error('error');
    });

Asynchronous predicates: function(file, [encode], done: function(err, result)): void

A predicate must have three arguments. The third argument is a callback function to settle a result.

Call done with the second argument of true/false.

gulp.src('./**/*.*')
    .pipe(filter(function(file, encode, done) {
        setTimeout(function() {
            done(null, file.isBuffer()); // 1st argument must be falsy.
        }, 0);
    });

To fail the predicate, call done with the first argument of non-falsy value.

gulp.src('./**/*.*')
    .pipe(filter(function(file, encode, done) {
        setTimeout(function() {
            done(new Error('error'));
        }, 0);
    });

Promise predicates: function(file, done: function(err, result)): Promise.

A predicate must have one or two argument(s). It returns a fulfilling promise of boolean value true/false.

gulp.src('./**/*.*')
    .pipe(filter(function(file, encode) {
        return Promise.resolve(file.isBuffer());
    });

To fail the predicate, return a rejecting promise.

gulp.src('./**/*.*')
    .pipe(filter(function(file, encode) {
        return Promise.reject(new Error('error'));
    });

Release Notes

v0.3.0
- Update library dependency
- Update supporting version of Node.js
  - Now we support Node 6 or higher
v0.2.5
- Update supporting version of Node.js
- Fix assertion error message of or() filter

License

MIT License
- see LICENSE

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