Implement %TypedArray%.prototype.{reduce,reduceRight}

test/mjsunit/harmony/typedarray-reduce.js

+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-arrays
+
+var typedArrayConstructors = [
+  Uint8Array,
+  Int8Array,
+  Uint16Array,
+  Int16Array,
+  Uint32Array,
+  Int32Array,
+  Uint8ClampedArray,
+  Float32Array,
+  Float64Array
+];
+
+function clone(v) {
+  // Shallow-copies arrays, returns everything else verbatim.
+  if (v instanceof Array) {
+    // Shallow-copy an array.
+    var newArray = new Array(v.length);
+    for (var i in v) {
+      newArray[i] = v[i];
+    }
+    return newArray;
+  }
+  return v;
+}
+
+
+// Creates a callback function for reduce/reduceRight that tests the number
+// of arguments and otherwise behaves as "func", but which also
+// records all calls in an array on the function (as arrays of arguments
+// followed by result).
+function makeRecorder(func, testName) {
+  var record = [];
+  var f = function recorder(a, b, i, s) {
+    assertEquals(4, arguments.length,
+                 testName + "(number of arguments: " + arguments.length + ")");
+    assertEquals("number", typeof(i), testName + "(index must be number)");
+    assertEquals(s[i], b, testName + "(current argument is at index)");
+    if (record.length > 0) {
+      var prevRecord = record[record.length - 1];
+      var prevResult = prevRecord[prevRecord.length - 1];
+      assertEquals(prevResult, a,
+                   testName + "(prev result -> current input)");
+    }
+    var args = [clone(a), clone(b), i, clone(s)];
+    var result = func.apply(this, arguments);
+    args.push(clone(result));
+    record.push(args);
+    return result;
+  };
+  f.record = record;
+  return f;
+}
+
+
+function testReduce(type,
+                    testName,
+                    expectedResult,
+                    expectedCalls,
+                    array,
+                    combine,
+                    init) {
+  var rec = makeRecorder(combine);
+  var result;
+  var performsCall;
+  if (arguments.length > 6) {
+    result = array[type](rec, init);
+  } else {
+    result = array[type](rec);
+  }
+  var calls = rec.record;
+  assertEquals(expectedCalls.length, calls.length,
+               testName + " (number of calls)");
+  for (var i = 0; i < expectedCalls.length; i++) {
+    assertEquals(expectedCalls[i], calls[i],
+                 testName + " (call " + (i + 1) + ")");
+  }
+  assertEquals(expectedResult, result, testName + " (result)");
+}
+
+
+function sum(a, b) { return a + b; }
+function prod(a, b) { return a * b; }
+function dec(a, b, i, arr) { return a + b * Math.pow(10, arr.length - i - 1); }
+function accumulate(acc, elem, i) { acc[i] = elem; return acc; }
+
+for (var constructor of typedArrayConstructors) {
+  // ---- Test Reduce[Left]
+
+  var simpleArray = new constructor([2,4,6])
+
+  testReduce("reduce", "SimpleReduceSum", 12,
+             [[0, 2, 0, simpleArray, 2],
+              [2, 4, 1, simpleArray, 6],
+              [6, 6, 2, simpleArray, 12]],
+             simpleArray, sum, 0);
+
+  testReduce("reduce", "SimpleReduceProd", 48,
+             [[1, 2, 0, simpleArray, 2],
+              [2, 4, 1, simpleArray, 8],
+              [8, 6, 2, simpleArray, 48]],
+             simpleArray, prod, 1);
+
+  testReduce("reduce", "SimpleReduceDec", 246,
+             [[0, 2, 0, simpleArray, 200],
+              [200, 4, 1, simpleArray, 240],
+              [240, 6, 2, simpleArray, 246]],
+             simpleArray, dec, 0);
+
+  testReduce("reduce", "SimpleReduceAccumulate", [2, 4, 6],
+             [[[], 2, 0, simpleArray, [2]],
+              [[2], 4, 1, simpleArray, [2, 4]],
+              [[2,4], 6, 2, simpleArray, [2, 4, 6]]],
+             simpleArray, accumulate, []);
+
+
+  testReduce("reduce", "EmptyReduceSum", 0, [], new constructor([]), sum, 0);
+  testReduce("reduce", "EmptyReduceProd", 1, [], new constructor([]), prod, 1);
+  testReduce("reduce", "EmptyReduceDec", 0, [], new constructor([]), dec, 0);
+  testReduce("reduce", "EmptyReduceAccumulate", [], [], new constructor([]), accumulate, []);
+
+  testReduce("reduce", "EmptyReduceSumNoInit", 0, [], new constructor([0]), sum);
+  testReduce("reduce", "EmptyReduceProdNoInit", 1, [], new constructor([1]), prod);
+  testReduce("reduce", "EmptyReduceDecNoInit", 0, [], new constructor([0]), dec);
+
+  // ---- Test ReduceRight
+
+  testReduce("reduceRight", "SimpleReduceRightSum", 12,
+             [[0, 6, 2, simpleArray, 6],
+              [6, 4, 1, simpleArray, 10],
+              [10, 2, 0, simpleArray, 12]],
+             simpleArray, sum, 0);
+
+  testReduce("reduceRight", "SimpleReduceRightProd", 48,
+             [[1, 6, 2, simpleArray, 6],
+              [6, 4, 1, simpleArray, 24],
+              [24, 2, 0, simpleArray, 48]],
+             simpleArray, prod, 1);
+
+  testReduce("reduceRight", "SimpleReduceRightDec", 246,
+             [[0, 6, 2, simpleArray, 6],
+              [6, 4, 1, simpleArray, 46],
+              [46, 2, 0, simpleArray, 246]],
+             simpleArray, dec, 0);
+
+
+  testReduce("reduceRight", "EmptyReduceRightSum", 0, [], new constructor([]), sum, 0);
+  testReduce("reduceRight", "EmptyReduceRightProd", 1, [], new constructor([]), prod, 1);
+  testReduce("reduceRight", "EmptyReduceRightDec", 0, [], new constructor([]), dec, 0);
+  testReduce("reduceRight", "EmptyReduceRightAccumulate", [],
+             [], new constructor([]), accumulate, []);
+
+  testReduce("reduceRight", "EmptyReduceRightSumNoInit", 0, [], new constructor([0]), sum);
+  testReduce("reduceRight", "EmptyReduceRightProdNoInit", 1, [], new constructor([1]), prod);
+  testReduce("reduceRight", "EmptyReduceRightDecNoInit", 0, [], new constructor([0]), dec);
+
+  // Ignore non-array properties:
+
+  var arrayPlus = new constructor([1,2,3]);
+  arrayPlus[-1] = NaN;
+  arrayPlus["00"] = NaN;
+  arrayPlus["02"] = NaN;
+  arrayPlus["-0"] = NaN;
+  arrayPlus.x = NaN;
+
+  testReduce("reduce", "ArrayWithNonElementPropertiesReduce", 6,
+             [[0, 1, 0, arrayPlus, 1],
+              [1, 2, 1, arrayPlus, 3],
+              [3, 3, 2, arrayPlus, 6],
+             ], arrayPlus, sum, 0);
+
+  testReduce("reduceRight", "ArrayWithNonElementPropertiesReduceRight", 6,
+             [[0, 3, 2, arrayPlus, 3],
+              [3, 2, 1, arrayPlus, 5],
+              [5, 1, 0, arrayPlus, 6],
+             ], arrayPlus, sum, 0);
+
+
+  // Test error conditions:
+
+  var exception = false;
+  try {
+    new constructor([1]).reduce("not a function");
+  } catch (e) {
+    exception = true;
+    assertTrue(e instanceof TypeError,
+               "reduce callback not a function not throwing TypeError");
+    assertTrue(e.message.indexOf(" is not a function") >= 0,
+               "reduce non function TypeError type");
+  }
+  assertTrue(exception);
+
+  exception = false;
+  try {
+    new constructor([1]).reduceRight("not a function");
+  } catch (e) {
+    exception = true;
+    assertTrue(e instanceof TypeError,
+               "reduceRight callback not a function not throwing TypeError");
+    assertTrue(e.message.indexOf(" is not a function") >= 0,
+               "reduceRight non function TypeError type");
+  }
+  assertTrue(exception);
+
+  exception = false;
+  try {
+    new constructor([]).reduce(sum);
+  } catch (e) {
+    exception = true;
+    assertTrue(e instanceof TypeError,
+               "reduce no initial value not throwing TypeError");
+    assertEquals("Reduce of empty array with no initial value", e.message,
+                 "reduce no initial TypeError type");
+  }
+  assertTrue(exception);
+
+  exception = false;
+  try {
+    new constructor([]).reduceRight(sum);
+  } catch (e) {
+    exception = true;
+    assertTrue(e instanceof TypeError,
+               "reduceRight no initial value not throwing TypeError");
+    assertEquals("Reduce of empty array with no initial value", e.message,
+                 "reduceRight no initial TypeError type");
+  }
+  assertTrue(exception);
+
+  // Reduce fails when called on non-TypedArrays
+  assertThrows(function() {
+    constructor.prototype.reduce.call([], function() {}, null);
+  }, TypeError);
+  assertThrows(function() {
+    constructor.prototype.reduceRight.call([], function() {}, null);
+  }, TypeError);
+
+  // Shadowing length doesn't affect every, unlike Array.prototype.every

[adamk, 2015/06/04 16:10:10]

Stray comment, fine to fix this in a followup (want to get this landed asap for
staging purposes).

+  var a = new constructor([1, 2]);
+  Object.defineProperty(a, 'length', {value: 1});
+  assertEquals(a.reduce(sum, 0), 3);
+  assertEquals(Array.prototype.reduce.call(a, sum, 0), 1);
+  assertEquals(a.reduceRight(sum, 0), 3);
+  assertEquals(Array.prototype.reduceRight.call(a, sum, 0), 1);
+
+  assertEquals(1, constructor.prototype.reduce.length);
+  assertEquals(1, constructor.prototype.reduceRight.length);
+}