javascript calling console.log function with variable length

Question

i want to call console.log function with variable length argument

function debug_anything() {
  var x = arguments;
  var p = 'DEBUG from ' + (new Error).stack.split("\n")[2];
  switch(x.length) {
    case 0: console.log(p); break;
    case 1: console.log(p,x[0]); break;
    case 2: console.log(p,x[0],x[1]); break;
    case 3: console.log(p,x[0],x[1],x[2]); break;
    case 4: console.log(p,x[0],x[1],x[2],x[3]); break;
    // so on..
  }
}

is there any (shorter) other way, note that i do not want this solution (since other methods from the x object (Argument or array) would be outputted.

console.log(p,x);

See my answer over here. http://stackoverflow.com/a/14667091 Regards, Hans — , Feb 02 '13 at 22:46

Gabriel Gartz · Answer 1 · 2016-11-29T22:30:02.293

5

Yes, you can use apply

console.log.apply(console, /* your array here */);

The full code:

function debug_anything() {
  // convert arguments to array
  var x = Array.prototype.slice.call(arguments, 0);

  var p = 'DEBUG from ' + (new Error).stack.split("\n")[2];

  // Add p to the beggin of x
  x.unshift(p);
  // do the apply magic again
  console.log.apply(console, x);
}

edited Nov 29 '16 at 22:30

answered Jan 05 '13 at 06:48

Gabriel Gartz

2,840
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ERROR! Uncaught TypeError: Function.prototype.apply: Arguments list has wrong type – Kokizzu Jan 05 '13 at 06:53
1

@Kiswono Prayogo: because of `.call`, not `.apply`. And `console`, not `this` – zerkms Jan 05 '13 at 06:53
@KiswonoPrayogo I do a better example to fix it. – Gabriel Gartz Jan 05 '13 at 06:55
1

@KiswonoPrayogo sorry, but for log works was needed to pass `console` as it context. It will work now, you don't need to convert arguments to array if you want, but if you are using a array is better that must be an array hehe – Gabriel Gartz Jan 05 '13 at 07:01

score 3 · Accepted Answer · answered Jan 05 '13 at 06:59

3

function debug_anything() {
  var x = arguments;
  var p = 'DEBUG from ' + (new Error).stack.split("\n")[2];
    console.log.apply(console, [p].concat(Array.prototype.slice.call(x)));
}

answered Jan 05 '13 at 06:59

Lyn Headley

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+1 I like your code style, do the same as my one, but is stylish! – Gabriel Gartz Jan 05 '13 at 07:03

epoch · Answer 3 · 2013-01-05T06:58:42.527

1

Just join the array

function debug_anything() {
  var x = Array.prototype.slice.call(arguments, 0);
  var p = 'DEBUG from ' + (new Error).stack.split("\n")[2];

  console.log(p, x.join(', '));
}

edited Jan 05 '13 at 06:58

answered Jan 05 '13 at 06:47

epoch

16,396
4
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ERROR: Uncaught TypeError: Object # – Kokizzu Jan 05 '13 at 06:56

javascript calling console.log function with variable length

3 Answers3