filtering 2d arrays using javascript

Question

I have a 2D array where I need to filter the rows having date field (3d column)

var data = [
[\'1\',\'a\',\'12-12-2019\',\'A\'],
[\'2\',\'b\',\'\',\'A\'],
[\'3\'         


        

Answer 1

Use Array#filter method with Array#some method.

var data = [
  ['1', 'a', '12-12-2019', 'A'],
  ['2', 'b', '', 'A'],
  ['3', 'c', '12-1-2019', 'A'],
  ['4', 'd', '', 'A'],
];

// check any of the string matched date pattern
let res = data.filter(arr => arr.some(str => /^\d{1,2}-\d{1,2}-\d{4}$/.test(str)))

console.log(res)

For the older browser, you can just do it with Array#filter method.

var data = [
  ['1', 'a', '12-12-2019', 'A'],
  ['2', 'b', '', 'A'],
  ['3', 'c', '12-1-2019', 'A'],
  ['4', 'd', '', 'A'],
];


var res = data.filter(function(arr) {
  // check length of date formated elements
  return arr.filter(function(str) {
    return /^\d{1,2}-\d{1,2}-\d{4}$/.test(str)
  }).length;
});

console.log(res)

---

If you just want to check the 3rd element always then there isn't any need of the nested loop.

var data = [
  ['1', 'a', '12-12-2019', 'A'],
  ['2', 'b', '', 'A'],
  ['3', 'c', '12-1-2019', 'A'],
  ['4', 'd', '', 'A'],
];


var res = data.filter(function(arr) {
  // check 3rd value is correct date value
  return /^\d{1,2}-\d{1,2}-\d{4}$/.test(arr[0])
  // if value would be empty all other case then simply 
  // return the value since empty values are falsy
  // return arr[2];
});

console.log(res)