28 lines
1,001 B
JavaScript
28 lines
1,001 B
JavaScript
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'use strict';
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let fastProto = null;
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// Creates an object with permanently fast properties in V8. See Toon Verwaest's
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// post https://medium.com/@tverwaes/setting-up-prototypes-in-v8-ec9c9491dfe2#5f62
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// for more details. Use %HasFastProperties(object) and the Node.js flag
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// --allow-natives-syntax to check whether an object has fast properties.
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function FastObject(o) {
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// A prototype object will have "fast properties" enabled once it is checked
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// against the inline property cache of a function, e.g. fastProto.property:
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// https://github.com/v8/v8/blob/6.0.122/test/mjsunit/fast-prototype.js#L48-L63
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if (fastProto !== null && typeof fastProto.property) {
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const result = fastProto;
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fastProto = FastObject.prototype = null;
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return result;
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}
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fastProto = FastObject.prototype = o == null ? Object.create(null) : o;
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return new FastObject;
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}
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// Initialize the inline property cache of FastObject
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FastObject();
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module.exports = function toFastproperties(o) {
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return FastObject(o);
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};
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