function-toString-builtin.js

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// Greatly (!) simplified patterns for the PropertyName production.

var propertyName = [

    // PropertyName :: LiteralPropertyName :: IdentifierName

    "\\w+",

    // PropertyName :: LiteralPropertyName :: StringLiteral

    "(?:'[^']*')",

    "(?:\"[^\"]*\")",

    // PropertyName :: LiteralPropertyName :: NumericLiteral

    "\\d+",

    // PropertyName :: ComputedPropertyName

    "(?:\\[[^\\]]+\\])",

].join("|")

var nativeCode = RegExp([

    "^", "function", ("(?:" + propertyName + ")?"), "\\(", "\\)", "\\{", "\\[native code\\]", "\\}", "$"

].join("\\s*"));

// Bound functions are considered built-ins.

reportMatch(nativeCode, function(){}.bind().toString());

reportMatch(nativeCode, function fn(){}.bind().toString());

// Built-ins which are well-known intrinsic objects.

reportMatch(nativeCode, Array.toString());

reportMatch(nativeCode, Object.prototype.toString.toString());

reportMatch(nativeCode, decodeURI.toString());

// Other built-in functions.

reportMatch(nativeCode, Math.asin.toString());

reportMatch(nativeCode, String.prototype.blink.toString());

reportMatch(nativeCode, RegExp.prototype[Symbol.split].toString());

// Built-in getter functions.

reportMatch(nativeCode, Object.getOwnPropertyDescriptor(RegExp.prototype, "flags").get.toString());

reportMatch(nativeCode, Object.getOwnPropertyDescriptor(Object.prototype, "__proto__").get.toString());

// Built-in setter functions.

reportMatch(nativeCode, Object.getOwnPropertyDescriptor(Object.prototype, "__proto__").set.toString());