diff options
Diffstat (limited to 'src/node_modules/es-abstract/2018/SpeciesConstructor.js')
-rw-r--r-- | src/node_modules/es-abstract/2018/SpeciesConstructor.js | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/src/node_modules/es-abstract/2018/SpeciesConstructor.js b/src/node_modules/es-abstract/2018/SpeciesConstructor.js new file mode 100644 index 0000000..3cdcd74 --- /dev/null +++ b/src/node_modules/es-abstract/2018/SpeciesConstructor.js @@ -0,0 +1,32 @@ +'use strict'; + +var GetIntrinsic = require('../GetIntrinsic'); + +var $species = GetIntrinsic('%Symbol.species%', true); +var $TypeError = GetIntrinsic('%TypeError%'); + +var IsConstructor = require('./IsConstructor'); +var Type = require('./Type'); + +// https://ecma-international.org/ecma-262/6.0/#sec-speciesconstructor + +module.exports = function SpeciesConstructor(O, defaultConstructor) { + if (Type(O) !== 'Object') { + throw new $TypeError('Assertion failed: Type(O) is not Object'); + } + var C = O.constructor; + if (typeof C === 'undefined') { + return defaultConstructor; + } + if (Type(C) !== 'Object') { + throw new $TypeError('O.constructor is not an Object'); + } + var S = $species ? C[$species] : void 0; + if (S == null) { + return defaultConstructor; + } + if (IsConstructor(S)) { + return S; + } + throw new $TypeError('no constructor found'); +}; |