Example 1: javascript array flatten
// flat(depth),
// depth is optional: how deep a nested array structure
// should be flattened.
// default value of depth is 1
const arr1 = [1, 2, [3, 4]];
arr1.flat();
// [1, 2, 3, 4]
const arr2 = [1, 2, [3, 4, [5, 6]]];
arr2.flat();
// [1, 2, 3, 4, [5, 6]]
const arr3 = [1, 2, [3, 4, [5, 6]]];
arr3.flat(2);
// [1, 2, 3, 4, 5, 6]
const arr4 = [1, 2, [3, 4, [5, 6, [7, 8, [9, 10]]]]];
arr4.flat(Infinity);
// [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
Example 2: js convert array of arrays to array
// Converts array with multiple values into a single array with all items:
var merged = [].concat.apply([], arrays);
Example 3: .join in javascript
const elements = ['Sun', 'Earth', 'Moon'];
console.log(elements.join());
// output: "Sun,Earth,Moon"
console.log(elements.join(''));
// output: "SunEarthMoon"
console.log(elements.join('-'));
// output: "Sun-Earth-Moon"
Example 4: flatten an array in javascript
// Although this now may be an older version of how to faltten an
// array of arrays. I still want to post it so some may have an understanding
// of how it works
function falltenArray(arr) {
let result = [...arr];
let flattened = false;
let counter = 0;
while (flattened === false){
// checks to see if the element at the counter index is an array
if (Array.isArray(result[counter])){
// unpacks the current array element back into the array
result.splice(counter, 1, ...result[counter]);
// if so the counter should start at the beginning of the array
counter = 0;
} else {
counter += 1;
}
if (counter === result.length){
flattened = true;
}
}
return result;
}
Example 5: Javascript flatten array of arrays
var multiDimensionArray = [["a"],["b","c"],["d"]]; //array of arrays
var flatArray = Array.prototype.concat.apply([], multiDimensionArray); //flatten array of arrays
console.log(flatArray); // [ "a","b","c","d"];
Example 6: join array javascript
<html>
<select multiple class="select-colors">
<option>blue</option>
<option>green</option>
</select>
</html>
<script>
var myColorSelect = $(".select-colors").val().join();
console.log(myColorSelect);
</script>