Javascript - How to return a partial array from a function?

Question

I would like to insert in the middle of a columns array, many elements based on a parameter returned by the function getSpecificColumns(parameter).

The first one is working cause it is returning a single object, but is there any way to return many elements in the middle of the array?

$scope.getSpecificColumns = function (myParam) {
    return { field: "SpecificField1", format: "{0:c}" };
}

$scope.getSpecificColumnsNotWorking = function (myParam) {
    return { field: "SpecificField2", format: "{0:c}" },
           { field: "SpecificField3", format: "{0:c}" };
}  

$scope.positionMontantNavGridOptions = {
    height: 630,
    filterable: {
        mode: "row"
    },
    pageable: true,
    columns: [
        { field: "Field1", width: "200px" },
        { field: "Field2", title: "Field 2", width: "80px" },        
        getSpecificColumns(parameter),
        { field: "Field4" }
    ]
}

@hindmost Seems to be confusing maps and arrays. Although, I guess objects are implemented as hashmaps, which use arrays, so I guess they are technically associative arrays. — Carcigenicate
– Carcigenicate, Commented Aug 12, 2016 at 19:15

Amit · Accepted Answer · 2016-08-12 19:19:44Z

2

If you want to return an array, return an array:

$scope.getSpecificColumnsNotWorking = function (myParam) {
  return [{ field: "SpecificField2", format: "{0:c}" },
          { field: "SpecificField3", format: "{0:c}" }];
}

A expression such as:

{ field: "SpecificField2", format: "{0:c}" },{ field: "SpecificField3", format: "{0:c}" };

evaluates to the former of the comma delimeted "sub-expressions", for example:

var a = 1, b = 2;
var c = a, b;
alert(c === a);

and in your original code this directly translates to the first literal object being returned from the function while the later is "discarded".

(By the way, if you're not using the myParam argument you might as well not define it and not pass it in the call)

edited Aug 12, 2016 at 19:19

answered Aug 12, 2016 at 19:12

Amit

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Comments

Hamlet Hakobyan · Accepted Answer · 2016-08-12 19:14:56Z

1

First return array, then use Array.prototype.concat to flaten it into array. Is this a suitable solution for your problem?

$scope.getSpecificColumnsNotWorking = function (myParam) {
    return [
        { field: "SpecificField2", format: "{0:c}" },
        { field: "SpecificField3", format: "{0:c}" }
    ];
}  

columns: [].concat(
    { field: "Field1", width: "200px" },
    { field: "Field2", title: "Field 2", width: "80px" },        
    getSpecificColumnsNotWorking (parameter),
    { field: "Field4" });

answered Aug 12, 2016 at 19:14

Hamlet Hakobyan

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1 Comment

Vincent Over a year ago

This is what I was looking for.

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