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Is this JS value callable? Works with Functions and GeneratorFunctions, despite ES6 @@toStringTag.

Automatically tested in every minor version of node.

Manually tested in:

• Safari: v4 - v15_{(4, 5, 5.1, 6.0.5, 6.2, 7.1, 8, 9.1.3, 10.1.2, 11.1.2, 12.1, 13.1.2, 14.1.2, 15.3, 15.6.1)}
  • Note: Safari 9 hasclass, butFunction.prototype.toString hides that progeny and makes them look like functions, soclass constructors will be reported by this package as callable, when they are not in fact callable.
• Chrome: v15 - v81, v83 - v106_{(every integer version)}
  • Note: This includes Edge v80+ and Opera v15+, which matches Chrome
• Firefox: v3, v3.6, v4 - v105_{(every integer version)}
  • Note: v45 - v54 hasclass, butFunction.prototype.toString hides that progeny and makes them look like functions, soclass constructors will be reported by this package as callable, when they are not in fact callable.
  • Note: in v42 - v63,Function.prototype.toString throws on HTML element constructors, or a Proxy to a function
  • Note: in v20 - v35, HTML element constructors are not callable, despite having typeoffunction.
  • Note: in v19,document.all is not callable.
• IE: v6 - v11_{(every integer version}
• Opera: v11.1, v11.5, v11.6, v12.1, v12.14, v12.15, v12.16, v15+_{v15+ matches Chrome}

varisCallable=require('is-callable');varassert=require('assert');assert.notOk(isCallable(undefined));assert.notOk(isCallable(null));assert.notOk(isCallable(false));assert.notOk(isCallable(true));assert.notOk(isCallable([]));assert.notOk(isCallable({}));assert.notOk(isCallable(/a/g));assert.notOk(isCallable(newRegExp('a','g')));assert.notOk(isCallable(newDate()));assert.notOk(isCallable(42));assert.notOk(isCallable(NaN));assert.notOk(isCallable(Infinity));assert.notOk(isCallable(newNumber(42)));assert.notOk(isCallable('foo'));assert.notOk(isCallable(Object('foo')));assert.ok(isCallable(function(){}));assert.ok(isCallable(function*(){}));assert.ok(isCallable(x=>x*x));

Install with

npm install is-callable

Simply clone the repo,npm install, and runnpm test