function API: function.arguments (as per ES1 spec)

The arguments prop - discouraged since 1997 (and might not work)

WHEN reading arguments in the function body THEN it is an array-like object containing all parameters the function was called with

let args; const fn = function() { args = arguments; } fn(1, 'abc', {x: 'y'}); assert.deepStrictEqual(Array.from(args), [1, 'abc', {x: 'y'}]);

WHEN arguments is defined inside a function THEN this is NOT overridden

//: {"jskatas": {"runnerOptions": {"strictMode": false}}} const fn = function() { const arguments = 'arg'; return arguments; } assert.equal(fn('the argument'), 'arg');

Links

spec docs The very first version of the spec defines this property already, the ES1 spec, see section 15.3.5.3 (PDF 732kB).