I have such an object
var data = [[1,2,34,4,5,6],[3,34,5,3,42,4],[,,,,,],[,,,],[,,,,,],[1,1]]
I need to filter it and get such a result:
var data = [[1,2,34,4,5,6],[3,34,5,3,42,4],[1,1]]
I tried to do it with array.filter() but I can't get the right expression.
Using filter and some
let a = [[1,2,34,4,5,6],[3,34,5,3,42,4],[,,,,,],[,,,],[,,,,,],[1,1]]
let final = a.filter(val=> val.some(v => true))
console.log(final)
[,,,,,].every(v => v === undefined). Since the given array literal by definition is an entirely sparse array (thus empty), it gets not iterated at all ... but the method every by definition also returns the true value for any empt array without running its provided callback function even once. Compare (a) [,,,,,].every(v => {console.log(v); return (v === undefined);}) with (b) [,,undefined,,,].every(v => {console.log(v); return (v === undefined);}) ...[,,undefined,,,] is not an empty array. It explicitly holds an undefined value at index 2 ... 2 in [,,undefined,,,] is true, whereas it is false for any other index in between 0 and 4. Thus a valid test for real array emptiness should be based on some ... e.g.: function isEmptyArray(arr) {return !arr.some(o => true); }
const result = array.map(it => it.filter(_ => true)).filter(sub => sub.length)
First of all, remove all the empty slots from the inner arrays, then remove all arrays with length 0.
it a double filter case: ( and the shortest code ) ;)
var data = [[1,2,34,4,5,6],[3,34,5,3,42,4],[,,,,,],[,,,],[,,,,,],[1,1]]
var R = data.filter(r=>r.filter(x=>x).length)
console.log( JSON.stringify(R) )
length > 0 part mate you can simply use data.filter(r=>r.filter(x=>x).length)Here you have a more declarative example. Hope it helps:
isArrayEmpty(arr) that returns a boolean that is true if an array is empty. To go deeper into detecting empty values in an array (not just falsy) see this stackoverflow thread. Also see Peter's comment.data excluding empty subarrays.var data = [[1,2,34,4,5,6],[3,34,5,3,42,4],[,,,,,],[,,,],[,,,,,],[1,1]]
var isArrayEmpty = arr => !arr.filter(elem => true).length;
var result = data.filter(subarray => !isArrayEmpty(subarray))
console.log(result)
isArrayEmpty might be reconsidered ... compare your's isArrayEmpty([,,,undefined,,,,]) with this approach ... function isEmptyArray(arr) {return !arr.some(o => true); } ... and isEmptyArray([,,,undefined,,,,]) ... see my 2 cents to @code-maniac 's answer above.let arr = [[1],[1,2],[,2],[,,],,[]]
console.log(JSON.stringify( arr.filter(a => 0 in a) ))
console.log(JSON.stringify( arr.filter(a => Object.keys(a).length) )) // to include sparse subarraysAnother alternative could be use reduce and some.
const data = [[1,2,34,4,5,6],[3,34,5,3,42,4],[,,,,,],[,,,],[,,,,,],[1,1]];
const filteredData = data.reduce((accumulator, currentValue) => {
if(currentValue.some(x => x)){
accumulator.push(currentValue);
}
return accumulator;
}, []);
console.log(filteredData);
var data = {...}