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assert: Check typed array view type in deepEqual
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Do not convert typed arrays to `Buffer` for deepEqual since
their values may not be accurately represented by 8-bit ints.
Instead perform binary comparison of underlying `ArrayBuffer`s,
but only when the array types match.

Never apply any kind of optimization for floating-point typed
arrays since bit pattern equality is not the right kind of check
for them.

PR-URL: #5910
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Fixes: #5907
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addaleax authored and Myles Borins committed Apr 5, 2016
1 parent 059b607 commit 0f5a51a
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Showing 2 changed files with 27 additions and 6 deletions.
17 changes: 13 additions & 4 deletions lib/assert.js
Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,7 @@ const compare = process.binding('buffer').compare;
const util = require('util');
const Buffer = require('buffer').Buffer;
const pSlice = Array.prototype.slice;
const pToString = (obj) => Object.prototype.toString.call(obj);

// 1. The assert module provides functions that throw
// AssertionError's when particular conditions are not met. The
Expand Down Expand Up @@ -170,10 +171,18 @@ function _deepEqual(actual, expected, strict) {
(expected === null || typeof expected !== 'object')) {
return strict ? actual === expected : actual == expected;

// If both values are instances of typed arrays, wrap them in
// a Buffer each to increase performance
} else if (ArrayBuffer.isView(actual) && ArrayBuffer.isView(expected)) {
return compare(new Buffer(actual), new Buffer(expected)) === 0;
// If both values are instances of typed arrays, wrap their underlying
// ArrayBuffers in a Buffer each to increase performance
// This optimization requires the arrays to have the same type as checked by
// Object.prototype.toString (aka pToString). Never perform binary
// comparisons for Float*Arrays, though, since e.g. +0 === -0 but their
// bit patterns are not identical.
} else if (ArrayBuffer.isView(actual) && ArrayBuffer.isView(expected) &&
pToString(actual) === pToString(expected) &&
!(actual instanceof Float32Array ||
actual instanceof Float64Array)) {
return compare(Buffer(actual.buffer),
Buffer(expected.buffer)) === 0;

// 7.5 For all other Object pairs, including Array objects, equivalence is
// determined by having the same number of owned properties (as verified
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16 changes: 14 additions & 2 deletions test/parallel/test-assert-typedarray-deepequal.js
Original file line number Diff line number Diff line change
Expand Up @@ -20,13 +20,25 @@ const equalArrayPairs = [
[new Int16Array(1e5), new Int16Array(1e5)],
[new Int32Array(1e5), new Int32Array(1e5)],
[new Float32Array(1e5), new Float32Array(1e5)],
[new Float64Array(1e5), new Float64Array(1e5)]
[new Float64Array(1e5), new Float64Array(1e5)],
[new Int16Array(256), new Uint16Array(256)],
[new Int16Array([256]), new Uint16Array([256])],
[new Float32Array([+0.0]), new Float32Array([-0.0])],
[new Float64Array([+0.0]), new Float32Array([-0.0])],
[new Float64Array([+0.0]), new Float64Array([-0.0])]
];

const notEqualArrayPairs = [
[new Uint8Array(2), new Uint8Array(3)],
[new Uint8Array([1, 2, 3]), new Uint8Array([4, 5, 6])],
[new Uint8ClampedArray([300, 2, 3]), new Uint8Array([300, 2, 3])]
[new Uint8ClampedArray([300, 2, 3]), new Uint8Array([300, 2, 3])],
[new Uint16Array([2]), new Uint16Array([3])],
[new Uint16Array([0]), new Uint16Array([256])],
[new Int16Array([0]), new Uint16Array([256])],
[new Int16Array([-256]), new Uint16Array([0xff00])], // same bits
[new Int32Array([-256]), new Uint32Array([0xffffff00])], // ditto
[new Float32Array([0.1]), new Float32Array([0.0])],
[new Float64Array([0.1]), new Float64Array([0.0])]
];

equalArrayPairs.forEach((arrayPair) => {
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