chore: Make startsWith faster (#6118)

by using built-in function (polyfill will handle IE).

core/touch.js

@@ -15,7 +15,6 @@
  */
 goog.module('Blockly.Touch');
 
-const utilsString = goog.require('Blockly.utils.string');
 /* eslint-disable-next-line no-unused-vars */
 const {Gesture} = goog.requireType('Blockly.Gesture');
 const {globalThis} = goog.require('Blockly.utils.global');
@@ -246,7 +245,7 @@ exports.checkTouchIdentifier = checkTouchIdentifier;
  * @alias Blockly.Touch.setClientFromTouch
  */
 const setClientFromTouch = function(e) {
-  if (utilsString.startsWith(e.type, 'touch') && e.changedTouches) {
+  if (e.type.startsWith('touch') && e.changedTouches) {
     // Map the touch event's properties to the event.
     const touchPoint = e.changedTouches[0];
     e.clientX = touchPoint.clientX;
@@ -263,9 +262,8 @@ exports.setClientFromTouch = setClientFromTouch;
  * @alias Blockly.Touch.isMouseOrTouchEvent
  */
 const isMouseOrTouchEvent = function(e) {
-  return utilsString.startsWith(e.type, 'touch') ||
-      utilsString.startsWith(e.type, 'mouse') ||
-      utilsString.startsWith(e.type, 'pointer');
+  return e.type.startsWith('touch') || e.type.startsWith('mouse') ||
+      e.type.startsWith('pointer');
 };
 exports.isMouseOrTouchEvent = isMouseOrTouchEvent;
 
@@ -276,8 +274,7 @@ exports.isMouseOrTouchEvent = isMouseOrTouchEvent;
  * @alias Blockly.Touch.isTouchEvent
  */
 const isTouchEvent = function(e) {
-  return utilsString.startsWith(e.type, 'touch') ||
-      utilsString.startsWith(e.type, 'pointer');
+  return e.type.startsWith('touch') || e.type.startsWith('pointer');
 };
 exports.isTouchEvent = isTouchEvent;
 

core/utils/parsing.js

@@ -15,7 +15,6 @@
 goog.module('Blockly.utils.parsing');
 
 const colourUtils = goog.require('Blockly.utils.colour');
-const stringUtils = goog.require('Blockly.utils.string');
 const {Msg} = goog.require('Blockly.Msg');
 
 
@@ -97,9 +96,8 @@ const tokenizeInterpolationInternal = function(
           // BKY_ is the prefix used to namespace the strings used in Blockly
           // core files and the predefined blocks in ../blocks/.
           // These strings are defined in ../msgs/ files.
-          const bklyKey = stringUtils.startsWith(keyUpper, 'BKY_') ?
-              keyUpper.substring(4) :
-              null;
+          const bklyKey =
+              keyUpper.startsWith('BKY_') ? keyUpper.substring(4) : null;
           if (bklyKey && bklyKey in Msg) {
             const rawValue = Msg[bklyKey];
             if (typeof rawValue === 'string') {

core/utils/string.js

@@ -19,17 +19,22 @@
  */
 goog.module('Blockly.utils.string');
 
+const deprecation = goog.require('Blockly.utils.deprecation');
+
 
 /**
- * Fast prefix-checker.
- * Copied from Closure's goog.string.startsWith.
+ * Obsolete prefix-checker.
  * @param {string} str The string to check.
  * @param {string} prefix A string to look for at the start of `str`.
  * @return {boolean} True if `str` begins with `prefix`.
  * @alias Blockly.utils.string.startsWith
+ * @deprecated April 2022. Use built-in string.startsWith.
  */
 const startsWith = function(str, prefix) {
-  return str.lastIndexOf(prefix, 0) === 0;
+  deprecation.warn(
+      'Blockly.utils.string.startsWith()', 'April 2022', 'April 2023',
+      'Use built-in string.startsWith');
+  return str.startsWith(prefix);
 };
 exports.startsWith = startsWith;
 

scripts/gulpfiles/chunks.json

@@ -131,9 +131,9 @@
     "./core/renderers/zelos/measurables/row_elements.js",
     "./core/renderers/zelos/marker_svg.js",
     "./core/renderers/zelos/measurables/inputs.js",
-    "./core/renderers/zelos/path_object.js",
     "./core/renderers/zelos/drawer.js",
     "./core/renderers/zelos/renderer.js",
+    "./core/renderers/zelos/path_object.js",
     "./core/field_textinput.js",
     "./core/field_image.js",
     "./core/renderers/zelos/constants.js",
@@ -229,7 +229,6 @@
     "./core/events/events_bubble_open.js",
     "./core/procedures.js",
     "./core/workspace_svg.js",
-    "./core/utils/rect.js",
     "./core/utils/deprecation.js",
     "./core/utils/svg_math.js",
     "./core/bubble_dragger.js",
@@ -242,6 +241,7 @@
     "./core/tooltip.js",
     "./core/block_svg.js",
     "./core/utils/size.js",
+    "./core/utils/rect.js",
     "./core/utils/coordinate.js",
     "./core/utils/style.js",
     "./core/dropdowndiv.js",

tests/mocha/utils_test.js

@@ -364,13 +364,6 @@ suite('Utils', function() {
   });
 
   suite('String', function() {
-    test('starts with', function() {
-      chai.assert.isFalse(Blockly.utils.string.startsWith('123', '2'), 'Does not start with');
-      chai.assert.isTrue(Blockly.utils.string.startsWith('123', '12'), 'Start with');
-      chai.assert.isTrue(Blockly.utils.string.startsWith('123', ''), 'Start with empty string 1');
-      chai.assert.isTrue(Blockly.utils.string.startsWith('', ''), 'Start with empty string 12');
-    });
-
     test('shortest string length', function() {
       let len = Blockly.utils.string.shortestStringLength('one,two,three,four,five'.split(','));
       chai.assert.equal(len, 3, 'Length of "one"');

typings/blockly.d.ts

@@ -100,15 +100,6 @@ declare module "core/utils/colour" {
     export function hueToHex(hue: number): string;
 }
 declare module "core/utils/string" {
-    /**
-     * Fast prefix-checker.
-     * Copied from Closure's goog.string.startsWith.
-     * @param {string} str The string to check.
-     * @param {string} prefix A string to look for at the start of `str`.
-     * @return {boolean} True if `str` begins with `prefix`.
-     * @alias Blockly.utils.string.startsWith
-     */
-    export function startsWith(str: string, prefix: string): boolean;
     /**
      * Given an array of strings, return the length of the shortest one.
      * @param {!Array<string>} array Array of strings.
@@ -8041,7 +8032,7 @@ declare module "core/renderers/common/constants" {
          *     colourTertiary:(string|undefined),
          *     hat:(string|undefined)
          * }} blockStyle A full or partial block style object.
-      
+
          * @return {!Theme.BlockStyle} A full block style object, with all
          *     required properties populated.
          * @protected