Filling an array by 1~100 without loop in javascript -

i investigating question raised in interview. interviewer ask piece of code fill array 1~100 without traditional loop. of course, couldn't tell him need type 1~100 in code "[1,2,3,4...100]".

i have thought several solutions, 1 of them successes. using mozilla firefox 46.0.1 & firebug.

solution 1(failed)

var filled = new array(100);  filled.map(function(val, index){    return index+1;  });    // array size 100 , filled undefined not int  console.info(filled);

solution 2(failed)

var filled = new array(100);  // seems can't go callback function  filled.foreach(function(val, index){    val = index+1;  });    // it's same solution 1  console.info(filled);

solution 3(failed)

var filled = [];  // guess root cause array doesn't initialized.  // if insert value index 99, previous 99 values automatically filled undefined.  filled[99] = 100;  filled.map(function(val, index){    // 100:99 can printed    console.info(val + ":" + index);    return index+1;  });  // array full undefined besides last value.  console.info(filled);

solution 4(successed) search stackoverflow , find solution.

var filled = array.apply(null, array(100))    .map(function(val, index) {       return index+1;    });    console.info(filled);

investigation of solution 4 try change in solution 4 , find truth.

// break chain , doesn't work. it's strange.  var filled = array.apply(null, new array(100));  filled.map(function(val, index) {       return index+1;    });    console.info(filled);

// in opinion, array.apply(null, array(100)) = this.array(undefined, undefined,...,undefined);  // so, start test    // works  var filled = this.array(undefined, undefined, undefined).map(function(val, index) {       return index+1;    });  console.info(filled);    // doesn't work  var filled = this.array(undefined, undefined, undefined);  filled.map(function(val, index) {       return index+1;    });  console.info(filled);

according above investigation, firmly trust chain coding key point. so, following code still failed.

var filled = new array(100).map(function(val, index) {       return index+1;    });  console.info(filled);

i confused situation, please explain it? thank help.

you can make new array defined length , apply array#map it.

the map() method creates new array results of calling provided function on every element in array. [emphasis ns]

most of tries, forgot assign map result.

var filled = array.apply(null, { length: 100 }).map(function (_, i) {      return + 1;  });    document.write('<pre>' + json.stringify(filled, 0, 4) + '</pre>');