i have tried with filter method but it removes all values. i'm getting this undefined value because of this function. I want to merge these three arrays and remove only undefined.
Example Arrays values:
let arry1= ["txt", "txt2"];
let arry2= ["txt"];
let arry3= ["txt", "txt5", "txt6"]
let c = arry1.map(function(value, index) {
return `${value} ${arry2[index]} ${arry3[index]}` ;
});
c = ['txt txt txt', 'txt2 undefined undefined']
i have this
let a = ["undefined this", "that undefined ", "undefined value undefined"]
// i want this
let a = ["this", "that", "value"]
```
you can write it like this
let a=arry1.map(function(value, index) {
value=`${value} ${arry2[index]||""}`.trim();
return `${value} ${arry3[index]||""}`.trim() ;
});
The other answers don't discriminate between the lack of a value (undefined) at an array element vs having the literal string "undefined" at an array element.
I've explained how to accommodate for that using comments in the code below:
const array1 = ["txt", "txt2"];
const array2 = ["txt"];
const array3 = ["txt", "txt5", "txt6"];
// Collect the arrays into another array so that we can iterate over them:
const arrays = [array1, array2, array3];
// Create an array of the lengths of the arrays:
const arrayLengths = arrays.map(({length}) => length);
// Get the maximum value from the lengths:
const maxLength = Math.max(...arrayLengths);
const result = [];
// One outer loop for each index of the longest array:
for (let i = 0; i < maxLength; i += 1) {
// A placeholder string:
let str = '';
// One inner loop for each of the arrays:
for (const array of arrays) {
// The value at the current index of the current array:
const strOrUndefined = array[i];
// If it's actually a string, then append a space and the string
// to the placeholder string:
if (typeof strOrUndefined === 'string') str += ` ${strOrUndefined}`;
}
// Push the placeholder string into the result array,
// but first remove the extra space created by the first iteration:
result.push(str.trimStart());
}
console.log(result); // ["txt txt txt", "txt2 txt5", "txt6"]