How Can I List All Methods of an Object?

How to Display All Methods of an Object

Problem:

Determine a method to list all available methods for a given object, similar to:

 alert(show_all_methods(Math));

Expected output:

abs, acos, asin, atan, atan2, ceil, cos, exp, floor, log, max, min, pow, random,round, sin, sqrt, tan, …

Solution:

To enumerate all properties, including methods, belonging to an object, utilize the Object.getOwnPropertyNames() method. This method provides an array of property names:

console.log(Object.getOwnPropertyNames(Math));
//-> ["E", "LN10", "LN2", "LOG2E", "LOG10E", "PI", ...etc ]

Subsequently, employ the filter() method to isolate solely the methods:

console.log(Object.getOwnPropertyNames(Math).filter(function (p) {
    return typeof Math[p] === 'function';
}));
//-> ["random", "abs", "acos", "asin", "atan", "ceil", "cos", "exp", ...etc ]

Note for ES3 Browsers:

In ES3 browsers, such as IE 8 and earlier, built-in object properties are not enumerable. However, this exclusion does not apply to objects like window and document, which are typically defined by the browser and likely enumerable.

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