Fix source maps

package.json

@@ -45,6 +45,7 @@
   },
   "dependencies": {
     "@babel/runtime": "^7.3.1",
+    "@gulp-sourcemaps/map-sources": "^1.0.0",
     "async-done": "^1.3.1",
     "core-js": "^2.6.5",
     "cross-fetch": "^3.0.1",
@@ -54,7 +55,6 @@
     "gulp": "^4.0.0",
     "gulp-babel": "^8.0.0",
     "gulp-ignore": "^2.0.2",
-    "gulp-sourcemaps": "^2.6.5",
     "gulp-yaml": "^2.0.3",
     "is-ci": "^2.0.0",
     "jscpd": "^2.0.6",

src/tasks/build.js

@@ -7,7 +7,7 @@ const { include } = require('gulp-ignore')
 const gulpBabel = require('gulp-babel')
 const del = require('del')
 const yamlToJson = require('gulp-yaml')
-const sourcemaps = require('gulp-sourcemaps')
+const mapSources = require('@gulp-sourcemaps/map-sources')
 
 const { BUILD, BUILD_DIST } = require('../files')
 const { getWatchTask } = require('../watch')
@@ -21,12 +21,11 @@ const copy = () =>
   }).pipe(dest(BUILD_DIST))
 
 const babel = () =>
-  src(`${BUILD}/**`, { dot: true, since: lastRun(babel) })
+  src(`${BUILD}/**`, { dot: true, since: lastRun(babel), sourcemaps: true })
     .pipe(include(/\.(js)$/u))
-    .pipe(sourcemaps.init())
     .pipe(gulpBabel({ comments: false, minified: true, retainLines: true }))
-    .pipe(sourcemaps.write('.', { sourceRoot }))
-    .pipe(dest(BUILD_DIST))
+    .pipe(mapSources(path => `${sourceRoot}/${path}`))
+    .pipe(dest(BUILD_DIST, { sourcemaps: '.' }))
 
 const sourceRoot = relative(BUILD_DIST, BUILD)