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Use hasOwnProperty to check for object properties
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I've been doing some performance profiling of Aphrodite and noticed that
even after updating to inline-style-prefixer 3.0.0, the prefixValue
function was still more expensive than I expected. After looking at the
CPU profile and the lines highlighted here, it seems that checking for
the existence of these object properties using `foo[bar]` is much more
expensive than checking using `foo.hasOwnProperty(bar)`.
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lencioni committed Mar 6, 2017
1 parent 11ba89c commit d9048b4
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Showing 14 changed files with 18 additions and 18 deletions.
2 changes: 1 addition & 1 deletion modules/dynamic/createPrefixer.js
Original file line number Diff line number Diff line change
Expand Up @@ -111,7 +111,7 @@ export default function createPrefixer(
}

// add prefixes to properties
if (this._requiresPrefix[property]) {
if (this._requiresPrefix.hasOwnProperty(property)) {
style[this._browserInfo.jsPrefix + capitalizeString(property)] = value
if (!this._keepUnprefixed) {
delete style[property]
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6 changes: 3 additions & 3 deletions modules/dynamic/plugins/flexboxIE.js
Original file line number Diff line number Diff line change
Expand Up @@ -36,7 +36,7 @@ export default function flexboxIE(
PluginMetaData
): ?Array<any> | ?any {
if (
(alternativeProps[property] ||
(alternativeProps.hasOwnProperty(property) ||
property === 'display' && typeof value === 'string' && value.indexOf('flex') > -1) &&
((browserName === 'ie_mob' || browserName === 'ie') && browserVersion === 10)
) {
Expand All @@ -45,10 +45,10 @@ PluginMetaData
if (!keepUnprefixed && !Array.isArray(style[property])) {
delete style[property]
}
if (property === 'display' && alternativeValues[value]) {
if (property === 'display' && alternativeValues.hasOwnProperty(value)) {
return getPrefixedValue(cssPrefix + alternativeValues[value], value, keepUnprefixed)
}
if (alternativeProps[property]) {
if (alternativeProps.hasOwnProperty(property)) {
style[alternativeProps[property]] = alternativeValues[value] || value
}
}
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4 changes: 2 additions & 2 deletions modules/dynamic/plugins/flexboxOld.js
Original file line number Diff line number Diff line change
Expand Up @@ -70,10 +70,10 @@ PluginMetaData
style.WebkitBoxDirection = 'normal'
}
}
if (property === 'display' && alternativeValues[value]) {
if (property === 'display' && alternativeValues.hasOwnProperty(value)) {
return getPrefixedValue(cssPrefix + alternativeValues[value], value, keepUnprefixed)
}
if (alternativeProps[property]) {
if (alternativeProps.hasOwnProperty(property)) {
style[alternativeProps[property]] = alternativeValues[value] || value
}
}
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2 changes: 1 addition & 1 deletion modules/dynamic/plugins/sizing.js
Original file line number Diff line number Diff line change
Expand Up @@ -29,7 +29,7 @@ export default function sizing(
): ?Array<any> | ?any {
// This might change in the future
// Keep an eye on it
if (properties[property] && values[value]) {
if (properties.hasOwnProperty(property) && values.hasOwnProperty(value)) {
return getPrefixedValue(cssPrefix + value, value, keepUnprefixed)
}
}
2 changes: 1 addition & 1 deletion modules/dynamic/plugins/transition.js
Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,7 @@ export default function transition(
style: Object,
{ cssPrefix, keepUnprefixed, requiresPrefix }: PluginMetaData
): ?Array<any> | ?any {
if (typeof value === 'string' && properties[property]) {
if (typeof value === 'string' && properties.hasOwnProperty(property)) {
// memoize the prefix array for later use
if (!requiresPrefixDashCased) {
requiresPrefixDashCased = Object.keys(requiresPrefix).map(prop => hyphenateProperty(prop))
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2 changes: 1 addition & 1 deletion modules/generator/generateDynamicPrefixMap.js
Original file line number Diff line number Diff line change
Expand Up @@ -37,7 +37,7 @@ export default function generateDynamicPrefixMap(browserList: Object): Object {

for (let i = 0, len = browsers.length; i < len; ++i) {
const browser = browsers[i]
if (!prefixMap[browser]) {
if (!prefixMap.hasOwnProperty(browser)) {
prefixMap[browser] = {}
}

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2 changes: 1 addition & 1 deletion modules/generator/generatePluginList.js
Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,7 @@ export default function getRecommendedPlugins(browserList: Object): Array<string
const browserSupportByPlugin = pluginMap[plugin]

for (const browser in browserSupportByPlugin) {
if (browserList[browser]) {
if (browserList.hasOwnProperty(browser)) {
const browserVersion = browserSupportByPlugin[browser]

if (browserList[browser] < browserVersion) {
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2 changes: 1 addition & 1 deletion modules/static/plugins/cursor.js
Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@ const values = {
}

export default function cursor(property: string, value: any): ?Array<string> {
if (property === 'cursor' && values[value]) {
if (property === 'cursor' && values.hasOwnProperty(value)) {
return prefixes.map(prefix => prefix + value)
}
}
2 changes: 1 addition & 1 deletion modules/static/plugins/flex.js
Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@ const values = {
}

export default function flex(property: string, value: any): ?Array<string> {
if (property === 'display' && values[value]) {
if (property === 'display' && values.hasOwnProperty(value)) {
return ['-webkit-box', '-moz-box', `-ms-${value}box`, `-webkit-${value}`, value]
}
}
2 changes: 1 addition & 1 deletion modules/static/plugins/flexboxIE.js
Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,7 @@ const alternativeProps = {
}

export default function flexboxIE(property: string, value: any, style: Object): void {
if (alternativeProps[property]) {
if (alternativeProps.hasOwnProperty(property)) {
style[alternativeProps[property]] = alternativeValues[value] || value
}
}
2 changes: 1 addition & 1 deletion modules/static/plugins/flexboxOld.js
Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,7 @@ export default function flexboxOld(property: string, value: any, style: Object):
style.WebkitBoxDirection = 'normal'
}
}
if (alternativeProps[property]) {
if (alternativeProps.hasOwnProperty(property)) {
style[alternativeProps[property]] = alternativeValues[value] || value
}
}
2 changes: 1 addition & 1 deletion modules/static/plugins/sizing.js
Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,7 @@ const values = {
}

export default function sizing(property: string, value: any): ?Array<any> {
if (properties[property] && values[value]) {
if (properties.hasOwnProperty(property) && values.hasOwnProperty(value)) {
return prefixes.map(prefix => prefix + value)
}
}
2 changes: 1 addition & 1 deletion modules/static/plugins/transition.js
Original file line number Diff line number Diff line change
Expand Up @@ -57,7 +57,7 @@ export default function transition(
propertyPrefixMap: Object
): ?string {
// also check for already prefixed transitions
if (typeof value === 'string' && properties[property]) {
if (typeof value === 'string' && properties.hasOwnProperty(property)) {
const outputValue = prefixValue(value, propertyPrefixMap)
// if the property is already prefixed
const webkitOutput = outputValue
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4 changes: 2 additions & 2 deletions modules/utils/getBrowserInformation.js
Original file line number Diff line number Diff line change
Expand Up @@ -48,7 +48,7 @@ function getBrowserName(browserInfo: Object): ?string {
}

for (const browser in browserByCanIuseAlias) {
if (browserInfo[browser]) {
if (browserInfo.hasOwnProperty(browser)) {
return browserByCanIuseAlias[browser]
}
}
Expand All @@ -63,7 +63,7 @@ export default function getBrowserInformation(userAgent: string): Object | boole
const browserInfo = bowser._detect(userAgent)

for (const browser in prefixByBrowser) {
if (browserInfo[browser]) {
if (browserInfo.hasOwnProperty(browser)) {
const prefix = prefixByBrowser[browser]

browserInfo.jsPrefix = prefix
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