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assert: optimize code path for deepEqual Maps
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PR-URL: #14501
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
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BridgeAR authored and addaleax committed Aug 13, 2017
1 parent 1168410 commit a6539ec
Showing 1 changed file with 18 additions and 27 deletions.
45 changes: 18 additions & 27 deletions lib/assert.js
Original file line number Diff line number Diff line change
Expand Up @@ -349,10 +349,6 @@ function setEquiv(a, b, strict, memo) {
// This is a lazily initiated Set of entries which have to be compared
// pairwise.
var set = null;
// When the sets contain only value types (eg, lots of numbers), and we're in
// strict mode or if all entries strictly match, we don't need to match the
// entries in a pairwise way. In that case this initialization is done lazily
// to avoid the allocation & bookkeeping cost.
for (const val of a) {
// Note: Checking for the objects first improves the performance for object
// heavy sets but it is a minor slow down for primitives. As they are fast
Expand All @@ -373,7 +369,7 @@ function setEquiv(a, b, strict, memo) {

if (set !== null) {
for (const val of b) {
// In non-strict-mode we have to check if a primitive value is already
// We have to check if a primitive value is already
// matching and only if it's not, go hunting for it.
if (typeof val === 'object' && val !== null) {
if (!setHasEqualElement(set, val, strict, memo))
Expand Down Expand Up @@ -449,10 +445,13 @@ function mapHasLoosePrim(a, b, key1, memo, item1, item2) {
return false;

for (const val of setA) {
if (!setHasEqualElement(setB, val, false, memo))
if (typeof val === 'object' && val !== null) {
if (!setHasEqualElement(setB, val, false, memo))
return false;
} else if (!setB.has(val) && !setHasLoosePrim(setA, setB, val)) {
return false;
}
}

return true;
}

Expand All @@ -472,34 +471,26 @@ function mapHasEqualEntry(set, map, key1, item1, strict, memo) {
}

function mapEquiv(a, b, strict, memo) {
// Caveat: In non-strict mode, this implementation does not handle cases
// where maps contain two equivalent-but-not-reference-equal keys.
if (a.size !== b.size)
return false;

var set = null;

for (const [key, item1] of a) {
// By directly retrieving the value we prevent another b.has(key) check in
// almost all possible cases.
const item2 = b.get(key);
if (item2 === undefined) {
// Just like setEquiv above but in addition we have to make sure the
// values are also equal.
if (typeof key === 'object' && key !== null) {
if (set === null) {
set = new Set();
}
set.add(key);
// Note: we do not have to pass memo in this case as at least one item
// is undefined.
} else if ((!innerDeepEqual(item1, item2, strict) || !b.has(key)) &&
(strict || !mapHasLoosePrim(a, b, key, memo, item1))) {
if (typeof key === 'object' && key !== null) {
if (set === null) {
set = new Set();
}
set.add(key);
} else {
// By directly retrieving the value we prevent another b.has(key) check in
// almost all possible cases.
const item2 = b.get(key);
if ((item2 === undefined && !b.has(key) ||
!innerDeepEqual(item1, item2, strict, memo)) &&
(strict || !mapHasLoosePrim(a, b, key, memo, item1, item2))) {
return false;
}
} else if (!innerDeepEqual(item1, item2, strict, memo) &&
(strict || !mapHasLoosePrim(a, b, key, memo, item1, item2))) {
return false;
}
}

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