chore(web): drops a worker polyfill, makes another conditional

common/models/templates/src/priority-queue.ts

@@ -46,7 +46,7 @@ export default class PriorityQueue<Type> {
     // https://en.wikipedia.org/wiki/Min-max_heap
     this.comparator = comparator;
 
-    this.heap = Array.from(initialEntries ?? []);
+    this.heap = (initialEntries ?? []).slice(0);
     this.heapify();
   }
 
@@ -228,6 +228,6 @@ export default class PriorityQueue<Type> {
    * they will almost certainly be unsorted.
    */
   toArray(): Type[] {
-    return Array.from(this.heap);
+    return this.heap.slice(0);
   }
 }

common/models/templates/test/test-priority-queue.js

@@ -24,7 +24,7 @@ describe('Priority queue', function() {
 
   it('initializes well from pre-existing values', function() {
     let input = [1, 10, 2, 9, 3, 8, 4, 7, 5, 6];
-    let originalInput = Array.from(input);
+    let originalInput = input.slice(0);
     let queue = new PriorityQueue((a, b) => a - b, input);
 
     assert.deepEqual(input, originalInput);

common/web/lm-worker/build-polyfill-concatenator.js

@@ -81,8 +81,6 @@ let sourceFileSet = [
   loadPolyfill('src/polyfills/array.fill.js', 'src/polyfills/array.fill.js'),
   // Needed for Android / Chromium browser pre-45.
   loadPolyfill('src/polyfills/array.findIndex.js', 'src/polyfills/array.findIndex.js'),
-  // Needed for Android / Chromium browser pre-45.
-  loadPolyfill('src/polyfills/array.from.js', 'src/polyfills/array.from.js'),
   // Needed for Android / Chromium browser pre-47.
   loadPolyfill('src/polyfills/array.includes.js', 'src/polyfills/array.includes.js'),
   // For Object.values, for iteration over object-based associate arrays.

common/web/lm-worker/src/main/correction/classical-calculation.ts

@@ -69,11 +69,11 @@ export class ClassicalDistanceCalculation<TUnit = string, TInput extends EditTok
       this.resolvedDistances = Array(rowCount);
 
       for(let r = 0; r < rowCount; r++) {
-        this.resolvedDistances[r] = Array.from(other.resolvedDistances[r]);
+        this.resolvedDistances[r] = other.resolvedDistances[r].slice(0);
       }
 
-      this.inputSequence = Array.from(other.inputSequence);
-      this.matchSequence = Array.from(other.matchSequence);
+      this.inputSequence = other.inputSequence.slice(0);
+      this.matchSequence = other.matchSequence.slice(0);
       this.diagonalWidth = other.diagonalWidth;
     } else {
       this.resolvedDistances = [];

common/web/lm-worker/src/main/correction/distance-modeler.ts

@@ -143,7 +143,7 @@ export class SearchNode {
 
       // TODO:  transform.deleteRight currently not supported.
 
-      let inputPath = Array.from(this.priorInput);
+      let inputPath = this.priorInput.slice(0);
       inputPath.push(probMass);
       // Tokenize and iterate over input chars, adding them into the calc.
       for(let i=0; i < transform.insert.length; i++) {

common/web/lm-worker/src/polyfills/array.from.js

@@ -1,81 +0,0 @@
-// From https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/from
-// Any npm-based ones require use of `require`, which won't work for us.
-
-// Production steps of ECMA-262, Edition 6, 22.1.2.1
-if (!Array.from) {
-  Array.from = (function () {
-    var toStr = Object.prototype.toString;
-    var isCallable = function (fn) {
-      return typeof fn === 'function' || toStr.call(fn) === '[object Function]';
-    };
-    var toInteger = function (value) {
-      var number = Number(value);
-      if (isNaN(number)) { return 0; }
-      if (number === 0 || !isFinite(number)) { return number; }
-      return (number > 0 ? 1 : -1) * Math.floor(Math.abs(number));
-    };
-    var maxSafeInteger = Math.pow(2, 53) - 1;
-    var toLength = function (value) {
-      var len = toInteger(value);
-      return Math.min(Math.max(len, 0), maxSafeInteger);
-    };
-
-    // The length property of the from method is 1.
-    return function from(arrayLike/*, mapFn, thisArg */) {
-      // 1. Let C be the this value.
-      var C = this;
-
-      // 2. Let items be ToObject(arrayLike).
-      var items = Object(arrayLike);
-
-      // 3. ReturnIfAbrupt(items).
-      if (arrayLike == null) {
-        throw new TypeError('Array.from requires an array-like object - not null or undefined');
-      }
-
-      // 4. If mapfn is undefined, then let mapping be false.
-      var mapFn = arguments.length > 1 ? arguments[1] : void undefined;
-      var T;
-      if (typeof mapFn !== 'undefined') {
-        // 5. else
-        // 5. a If IsCallable(mapfn) is false, throw a TypeError exception.
-        if (!isCallable(mapFn)) {
-          throw new TypeError('Array.from: when provided, the second argument must be a function');
-        }
-
-        // 5. b. If thisArg was supplied, let T be thisArg; else let T be undefined.
-        if (arguments.length > 2) {
-          T = arguments[2];
-        }
-      }
-
-      // 10. Let lenValue be Get(items, "length").
-      // 11. Let len be ToLength(lenValue).
-      var len = toLength(items.length);
-
-      // 13. If IsConstructor(C) is true, then
-      // 13. a. Let A be the result of calling the [[Construct]] internal method 
-      // of C with an argument list containing the single item len.
-      // 14. a. Else, Let A be ArrayCreate(len).
-      var A = isCallable(C) ? Object(new C(len)) : new Array(len);
-
-      // 16. Let k be 0.
-      var k = 0;
-      // 17. Repeat, while k < len… (also steps a - h)
-      var kValue;
-      while (k < len) {
-        kValue = items[k];
-        if (mapFn) {
-          A[k] = typeof T === 'undefined' ? mapFn(kValue, k) : mapFn.call(T, kValue, k);
-        } else {
-          A[k] = kValue;
-        }
-        k += 1;
-      }
-      // 18. Let putStatus be Put(A, "length", len, true).
-      A.length = len;
-      // 20. Return A.
-      return A;
-    };
-  }());
-}

common/web/lm-worker/src/test/cases/edit-distance/context-tracker.js

@@ -21,7 +21,7 @@ describe('ContextTracker', function() {
         insert: '',
         deleteLeft: 0
       }
-      let newContext = Array.from(existingContext);
+      let newContext = existingContext.slice(0);
       newContext.splice(0, 1);
       let rawTokens = ["apple", null, "a", null, "day", null, "keeps", null, "the", null, "doctor"];
 
@@ -37,7 +37,7 @@ describe('ContextTracker', function() {
         insert: 'r',
         deleteLeft: 0
       }
-      let newContext = Array.from(existingContext);
+      let newContext = existingContext.slice(0);
       newContext[newContext.length - 1] = 'doctor';
       let rawTokens = ["an", null, "apple", null, "a", null, "day", null, "keeps", null, "the", null, "doctor"];
 
@@ -53,7 +53,7 @@ describe('ContextTracker', function() {
         insert: ' ',
         deleteLeft: 0
       }
-      let newContext = Array.from(existingContext);
+      let newContext = existingContext.slice(0);
       newContext.push('');
       let rawTokens = ["an", null, "apple", null, "a", null, "day", null, "keeps", null, "the", null, "doctor", null, ""];
 
@@ -73,7 +73,7 @@ describe('ContextTracker', function() {
         insert: 'a',
         deleteLeft: 0
       }
-      let newContext = Array.from(existingContext);
+      let newContext = existingContext.slice(0);
       newContext.push('a'); // The incoming transform should produce a new token WITH TEXT.
       let rawTokens = ["'", null, "a"];
 
@@ -93,7 +93,7 @@ describe('ContextTracker', function() {
         insert: ' ',
         deleteLeft: 0
       }
-      let newContext = Array.from(existingContext);
+      let newContext = existingContext.slice(0);
       newContext.splice(0, 1);
       newContext.push('');
       let rawTokens = ["apple", null, "a", null, "day", null, "keeps", null, "the", null, "doctor", null, ""];