I have seen dozens of questions asked for checking if an array is empty. But I can't find the question on how to check if the first item in an array is empty.
Currently, I am doing this check on this way, but I highly doubt that it is the correct way to do this.
var specialtiesListArray = ['', 'not', 'empty', 'value'];
if (specialtiesListArray[0] == '') {
specialtiesListArray.shift(); // <== Removing the first item when empty.
}
console.info({ specialtiesListArray });The above works fine, but I am wondering is this ok? Are there better ways. And if someone knows a duplicate, then please let me know. I gladly delete the question if it has already been answered.
I think your approach is just fine. You could create a function, and check array length before trying to read element at index 0:
export const removeFirstItemIfEmpty = (array) => {
if (array.length > 0 && array[0] == '') {
array.shift();
}
return array;
}
import { removeFirstItemIfEmpty } from './utils.js'
const result = removeFirstItemIfEmpty(['', 'not', 'empty', 'value']);
console.info({ result });
You could use filter and update the array.
specialtiesListArray = ['', 'not', 'empty', 'value'];
specialtiesListArray = specialtiesListArray.filter((item, index) => index!==0 && item !== '');
console.log(specialtiesListArray);The following function will remove anything that is undefined, null or empty but will allow the number 0 to pass:
var testArr = [['', null, 'not', 'empty', 'value'],[false,2,3,4],[undefined,"", null,"one","two"],[0,1,2,3]];
function ltrimArr(arr){
while (arr.length && !arr[0]&&arr[0]!==0) arr.shift();
return arr
}
testArr.forEach(a=>console.log(ltrimArr(a)))