How To Replace All Undefined Values In An Array With "-"?

I have an array like: var array = [1, 2, undefined, undefined, 7, undefined] and need to replace all undefined values with '-'. The result should be: var resultArray = [1, 2, '-',

Solution 1:

You could check for undefined and take '-', otherwise the value and use Array#map for getting a new array.

var array = [1, 2, undefined, undefined, 7, undefined],
    result = array.map(v => v === undefined ? '-' : v);
    
console.log(result);

For a sparse array, you need to iterate all indices and check the values.

var array = [1, 2, , , 7, ,],
    result = Array.from(array, v => v === undefined ? '-' : v);
    
console.log(result);

Solution 2:

You can use Array.map

var array = [1, 2, undefined, undefined, 7, undefined];
var newArray = array.map(x => x !== undefined ? x : "-");
console.log(newArray);

Solution 3:

You can map the values and return - if undefined.

let array = [1, 2, undefined, undefined, 7, undefined]

let result = array.map(o => o !== undefined ? o : '-');

console.log(result);

Solution 4:

var newArray = array.map(function(val) {
    if (typeof val === 'undefined') {
        return'-';
    }
    returnval;
});

Solution 5:

Try using this -

array.forEach(function(part,index,Arr){ if(!Arr[index])Arr[index]='-'})