每当杯表检测到文件更改时，打印新消息。

Question

每当任何一个js文件被更改时，我都会使用google闭包编译器和一站式监视来编译js文件。

这是密码；

var closureCompiler = require('google-closure-compiler').gulp();
var flatmap = require('gulp-flatmap');    
var watch = require('gulp-watch');

gulp.task('js-closure', function () {
    return watch(['app/js/*.js', 'dist/single.js'], function()
    {
        gulp.src(['app/js/*.js', 'dist/single.js'], {base: './'})
            .pipe(flatmap(function(stream, file) {
                return stream.pipe(closureCompiler({
                    compilation_level: 'SIMPLE_OPTIMIZATIONS',
                    warning_level: 'QUIET',
                    language_in: 'ECMASCRIPT6_STRICT',
                    language_out: 'ECMASCRIPT5_STRICT',
                    output_wrapper: '(function(){\n%output%\n}).call(this)',
                    js_output_file: path.basename(file.path).replace(/js$/, 'min.js')
                }))
            }))
            .pipe(gulp.dest('./dist/js'));
    });
});

效果很好。但是，当检测到js文件已更改并重新编译时，我想将新消息打印到终端。新的信息应该提供这样的信息；

1201hrs - file XXX was changed and recompiled

任何形式的伐木都会受到欢迎。

Answer 1

使用口口换位，它只通过已更改的源文件。吞咽记录器是一个基本的流记录器。

var gulp = require("gulp"),
    changedInPlace = require("gulp-changed-in-place"),
    logger = require("gulp-logger");

gulp.task("default", function () {
  return gulp.src("app/js/**/*.js")
    .pipe(changedInPlace())
    // the pipe now contains the files
    // that have changed since the last run
    .pipe(logger({
      before: "Closure compiler task",
      after: "Compiling complete!",
      showChange: true
    }))
    // your own gulp task goes here


    // then pipe to the destination
    .pipe(gulp.dest("./dist/js"));
});

Answer 2

下面是问题中提供的源代码所需的修改。这归功于Dan，他提供了使用gulp-changed-in-place和gulp-logger的提示。

var closureCompiler = require('google-closure-compiler').gulp();
var flatmap = require('gulp-flatmap');
var watch = require('gulp-watch');
var changedInPlace = require("gulp-changed-in-place");
var logger = require("gulp-logger");

gulp.task('js-closure', function () {
    return watch(['app/js/*.js', 'dist/single.js'], function()
    {
        gulp.src(['app/js/*.js', 'dist/single.js'], {base: './'})
            .pipe(changedInPlace())
            .pipe(flatmap(function(stream, file) {
                return stream.pipe(closureCompiler({
                    compilation_level: 'SIMPLE_OPTIMIZATIONS',
                    warning_level: 'QUIET',
                    language_in: 'ECMASCRIPT6_STRICT',
                    language_out: 'ECMASCRIPT5_STRICT',
                    output_wrapper: '(function(){\n%output%\n}).call(this)',
                    js_output_file: path.basename(file.path).replace(/js$/, 'min.js')
                }))
            }))
            .pipe(logger({
                before: "file was changed",
                after: "file has been recompiled",
                showChange: true
            }))
            .pipe(gulp.dest('./dist/js'));
    });
});