Call function in javascript gives error [duplicate]

Question

i am reading about call function in js. Now i have this code

var o = {
  name: 'i am object',
  age: 22
}

function saymyName(arguentToFunc) {
  console.log('my name is ' + this.name + 'and thw argument  passed is ' + arguentToFunc);
}

saymyName.apply(o, 'hello there');

But it gives an error message saying Uncaught TypeError: Function.prototype.apply: Arguments list has wrong type

In the book the definite guide it is written that the second argument is the value passed to the function. eg here it is hello there So why the error?

Hey according to the book .apply needs this what does If a function is defined to accept an arbitrary number of arguments, mean? i mean arbritary??

Hey why am i downvoted?

Cloudboy22
– Cloudboy22

2015-10-20 06:43:35 +00:00
Commented Oct 20, 2015 at 6:43 — Cloudboy22
– Cloudboy22, Commented Oct 20, 2015 at 6:43
@Yeah but i was confused!!

Cloudboy22
– Cloudboy22

2015-10-20 06:45:56 +00:00
Commented Oct 20, 2015 at 6:45 — Cloudboy22
– Cloudboy22, Commented Oct 20, 2015 at 6:45

Matteo Tassinari · Accepted Answer · 2015-10-20 06:42:21Z

3

apply requires an array of parameter, you should use it as

saymyName.apply(o, ['hello there']);

or else you could use call

saymyName.call(o, 'hello there');

answered Oct 20, 2015 at 6:42

Matteo Tassinari

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Comments

RobG · Accepted Answer · 2015-10-20 06:54:08Z

3

Use call instead of apply, as apply needs the second parameter to be an Array–like object.

Use apply when an array of values needs to be sent as parameters to the called function (e.g. to pass all the arguments of the currently executing function using the arguments object).

Demo

var o = {
  name: 'i am object',
  age: 22
};

function saymyName(arguentToFunc) {

  console.log('my name is ' + this.name + 'and thw argument  passed is ' + arguentToFunc);
}

saymyName.call(o, 'hello there');

Also, see bind for how to set a function's this to a fixed value, regardless of how it's called.

edited Oct 20, 2015 at 6:54

RobG

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answered Oct 20, 2015 at 6:42

Tushar

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5 Comments

Cloudboy22 Over a year ago

what does If a function is defined to accept an arbitrary number of arguments, mean? i mean arbritary??

poke Over a year ago

@MarcAndreJiacarrini Do we really need to tell you how to look up words in a dictionary?

Cloudboy22 Over a year ago

@poke the dictionary contains many meanings dude... which one will fit here... Mr. Cool guy??

RobG Over a year ago

@MarcAndreJiacarrini—"an arbitrary number" means any number, though functions can accept from 0 to ??? arguments.

Tushar Over a year ago

@RobG Thank you for improving answer :)

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