在JavaScript函数中返回多个值

Question

I'm trying to match test scores with values contained in the level array and to return selected values in an output array, But, when running the below script in the Firebug console I get the error message "TypeError: level is undefined". I don't understand this, the level seems well defined to me, maybe the error lies elsewhere.

var level =  [[905,990,"91% - 100%","International Professional Proficiency","Able to communicate effectively in any situation"],
    [785,900,"79% - 90%","Working Proficiency Plus","Able to satisfy most work requirements with language that is often, but not always, acceptable and effective"],
    [605,780,"61% - 78%","Limited Working Proficiency","Able to satisfy most social demands and limited work requirements "],
    [405,600,"41% - 60%","Elementary Proficiency Plus","Can initiate and maintain predictable face-to-face conversations and satisfy limited social demands"],
    [255,400,"26% - 40%","Elementary Proficiency","Speaker has functional, but limited proficiency. Able to maintain very simple face-to-face conversations on familiar topics"],
    [10,50, "0 - 25%","Basic Proficiency","Able to satisfy immediate survival needs"]];

function between(x, min, max) {                     
  return x >= min && x <= max;
}

var newProfic =  function profLevel(x, level) {
    var prof1, prof2, prof3;
    for(var i=0; i<level.length; i++) {
      if( between(x, level[i][0], level[i][1])) {
        prof1 = levell[i][2];
        prof2 = level[i][3];
        prof3 = level[i][4];
      }     
    }
    return  [ prof1,   prof2,  prof3 ];
  }

  var profic = newProfic();
  var prof1 = profic[0];
  var prof2 = profic[1]; 
  var prof3 = profic[2];  
  newProfic( 300,  level);

Any comments or help would be much appreciated. Thanks

Answer 1

The error message is actually:

 ReferenceError: levell is not defined 

You made a typo and added an extra l to one of your variables.

---

You also made another error:

 var profic = newProfic(); 

Here you call newProfic and the second argument is unspecified so it is undefined .

 var newProfic = function profLevel(x, level) { 

The second argument is level therefore level is undefined .

Answer 2

I suggest to use Array#filter and then Array#map to get the wanted elements.

This proposal expects zero, one or more than one result set.

 var level = [[905, 990, "91% - 100%", "International Professional Proficiency", "Able to communicate effectively in any situation"], [785, 900, "79% - 90%", "Working Proficiency Plus", "Able to satisfy most work requirements with language that is often, but not always, acceptable and effective"], [605, 780, "61% - 78%", "Limited Working Proficiency", "Able to satisfy most social demands and limited work requirements "], [405, 600, "41% - 60%", "Elementary Proficiency Plus", "Can initiate and maintain predictable face-to-face conversations and satisfy limited social demands"], [255, 400, "26% - 40%", "Elementary Proficiency", "Speaker has functional, but limited proficiency. Able to maintain very simple face-to-face conversations on familiar topics"], [10, 50, "0 - 25%", "Basic Proficiency", "Able to satisfy immediate survival needs"]]; function between(x, min, max) { return x >= min && x <= max; } function profLevel(x, level) { return level.filter(function (a) { return between(x, a[0], a[1]); }).map(function (a) { return [a[2], a[3], a[4]]; }); } console.log(profLevel(300, level)); 

 .as-console-wrapper { max-height: 100% !important; top: 0; } 

This proposal expects only one result set

 var level = [[905, 990, "91% - 100%", "International Professional Proficiency", "Able to communicate effectively in any situation"], [785, 900, "79% - 90%", "Working Proficiency Plus", "Able to satisfy most work requirements with language that is often, but not always, acceptable and effective"], [605, 780, "61% - 78%", "Limited Working Proficiency", "Able to satisfy most social demands and limited work requirements "], [405, 600, "41% - 60%", "Elementary Proficiency Plus", "Can initiate and maintain predictable face-to-face conversations and satisfy limited social demands"], [255, 400, "26% - 40%", "Elementary Proficiency", "Speaker has functional, but limited proficiency. Able to maintain very simple face-to-face conversations on familiar topics"], [10, 50, "0 - 25%", "Basic Proficiency", "Able to satisfy immediate survival needs"]]; function between(x, min, max) { return x >= min && x <= max; } function profLevel(x, level) { var index = -1; level.some(function (a, i) { if (between(x, a[0], a[1])) { index = i; return true; } }); if (index >= 0) { return [level[index][2], level[index][3], level[index][4]]; } } console.log(profLevel(300, level)); 

 .as-console-wrapper { max-height: 100% !important; top: 0; }