Html 引导程序将项目文件夹中的3迁移到4

我有一个任务文件，其中提到将所有BS3转换为BS4，但没有关于如何运行的说明。有没有一种方法可以让它运行在一个有角度的项目结构上，以取代所有的BS#到BS4

任务文件：

let gulp            = require('gulp'),
    replace         = require('gulp-batch-replace'),
    filesExist      = require('files-exist');

gulp.task('bt4', () =>
{
    let diff = {
        // bootstrap 2
        '@media (max-width: $screen-xxs)':          '@include media-breakpoint-down(xs)',

        '.col-*-offset-*':          '.offset-*',
        '.col-*-push-*':            '.order-*-2',
        '.col-*-pull-*':            '.order-*-1',
        '.panel':                   '.card',
        '.panel-heading':           '.card-header',

// other clasess
    };

    let replaceThis = [];
    Object.keys(diff).forEach(function(key)
    {
        replaceThis.push([key, diff[key]]);
    });

    return gulp
        .src(filesExist('./scss/**'))
        .pipe(replace(replaceThis))
        .pipe(gulp.dest('./build/scss'));
});

let gulp            = require('gulp'),
    replace         = require('gulp-batch-replace'),
    filesExist      = require('files-exist');

gulp.task('bt4', () =>
{
    let diff = {
        // bootstrap 2
        '@media (max-width: $screen-xxs)':          '@include media-breakpoint-down(xs)',

        '.col-*-offset-*':          '.offset-*',
        '.col-*-push-*':            '.order-*-2',
        '.col-*-pull-*':            '.order-*-1',
        '.panel':                   '.card',
        '.panel-heading':           '.card-header',

// other clasess
    };

    let replaceThis = [];
    Object.keys(diff).forEach(function(key)
    {
        replaceThis.push([key, diff[key]]);
    });

    return gulp
        .src(filesExist('./scss/**'))
        .pipe(replace(replaceThis))
        .pipe(gulp.dest('./build/scss'));
});