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Merge pull request #408 from griffpatch/optimisation/avoid-negative-index-lookups

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Optimisation - Avoid negative index lookups #407
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Andrew Sliwinski 2017-01-30 15:06:02 -05:00 committed by GitHub
commit c2a488a197
1 changed files with 4 additions and 4 deletions
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8
src/engine/thread.js
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@ -101,7 +101,7 @@ Thread.prototype.pushStack = function (blockId) {
if (this.stack.length > this.stackFrames.length) {
// Copy warp mode from any higher level.
var warpMode = false;
if (this.stackFrames[this.stackFrames.length - 1]) {
if (this.stackFrames.length > 0 && this.stackFrames[this.stackFrames.length - 1]) {
warpMode = this.stackFrames[this.stackFrames.length - 1].warpMode;
}
this.stackFrames.push({
@ -145,7 +145,7 @@ Thread.prototype.popStack = function () {
* @return {?string} Block ID on top of stack.
*/
Thread.prototype.peekStack = function () {
return this.stack[this.stack.length - 1];
return this.stack.length > 0 ? this.stack[this.stack.length - 1] : null;
};
@ -154,7 +154,7 @@ Thread.prototype.peekStack = function () {
* @return {?Object} Last stack frame stored on this thread.
*/
Thread.prototype.peekStackFrame = function () {
return this.stackFrames[this.stackFrames.length - 1];
return this.stackFrames.length > 0 ? this.stackFrames[this.stackFrames.length - 1] : null;
};
/**
@ -162,7 +162,7 @@ Thread.prototype.peekStackFrame = function () {
* @return {?Object} Second to last stack frame stored on this thread.
*/
Thread.prototype.peekParentStackFrame = function () {
return this.stackFrames[this.stackFrames.length - 2];
return this.stackFrames.length > 1 ? this.stackFrames[this.stackFrames.length - 2] : null;
};
/**