Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 | 35x 706x 17x 689x 17x 672x 38x 634x 2x 632x 1x 631x 34x 34x 34x 597x | /**
* Type detection beyond `typeof`
*
* Copyright (C) 2022 Dieter Raber
* https://opensource.org/licenses/MIT
*/
/**
* More consistent variety of `typeof`. It returns a string such as `Null`, `Undefined`, `Function`, `String`, etc.
* These values are case sensitive and mostly correspond to the constructor names.
* @param {*} value The value to check
* @returns {String}
* @example
* // getType() is not limited to the examples below
* const v1 = null;
* getType(v1); // "Null"
*
* let v2;
* getType(v2); // "Undefined"
*
* const v3 = function() {};
* getType(v3); // "Function", use isCallable() to cover async functions and generators as well
*
* const v4 = async function() {};
* getType(v4); // "AsyncFunction"
*
* const v5 = function* generator(i) {};
* getType(v5); // "GeneratorFunction"
*
* const v6 = { foo: "bar" };
* getType(v6); // "PlainObject", not "Object", as you may have expected
*
* const v7 = new Map();
* getType(v7); // "Map"
*
* const v8 = new Set();
* getType(v8); // "Set"
*
* const v9 = new WeakMap();
* getType(v9); // "WeakMap"
*
* const v10 = new WeakSet();
* getType(v10); // "WeakSet"
*
* const v11 = new Date();
* getType(v11); // "Date"
*
* const v12 = new Error();
* getType(v12); // "Error"
*
* const v13 = new Promise(() => {});
* getType(v13); // "Promise"
*
* class CustomClass {}
* const v14 = new CustomClass();
* getType(v14); // "CustomClass"
* getType(class CustomClass {}) // "Class", note the difference: CustomClass has not been initiated yet
*/
const getType = (value) => {
if (typeof value === "undefined") {
return "Undefined";
}
// `null` is an object, but has no constructor
if (value === null) {
return "Null";
}
// `Object` in this context is ambiguous, `PlainObject` on the other hand
// is pretty established in the industry and used by other libraries as well.
if (value.constructor.name === "Object") {
return "PlainObject";
}
// ES6 classes that aren't initiated with `new` would be reported with `Function`
// instead of `Class`. Parsing the input value as string can fix this
if (
value.constructor.name === "Function" &&
/^class\s+([\w]+\s+)?{/.test(value.toString().replace(/\s+/gs, " "))
) {
return "Class";
}
// Chrome at this point reports elements of the type `MathMLElement` wrongly as `Element`
if (value.constructor.name === "Element" && value.namespaceURI.endsWith('MathML')) {
return "MathMLElement";
}
// Work around objects with the own property `name` as a method
// @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/name#sect3
if (typeof value.constructor.name === "function") {
const match = value.constructor.toString().match(/[^\s]+\s+([\w]+)/);
Eif (match && match.length > 0) {
return match[1];
}
return "Object";
}
// The name of the constructor, for example `Array`, `Object`,
// `Number`, `String`, `Boolean` or `MyCustomObject`
return value.constructor.name;
};
export default getType;
|