src/plugins/popper/index.js
function findIndex(arr, prop, value) {
  // use native findIndex if supported
  if (Array.prototype.findIndex) {
    return arr.findIndex(function (cur) {
      return cur[prop] === value;
    });
  }

  // use `find` + `indexOf` if `findIndex` isn't supported
  var match = find(arr, function (obj) {
    return obj[prop] === value;
  });
  return arr.indexOf(match);
}
function findIndex(arr, prop, value) {
  // use native findIndex if supported
  if (Array.prototype.findIndex) {
    return arr.findIndex(function (cur) {
      return cur[prop] === value;
    });
  }

  // use `find` + `indexOf` if `findIndex` isn't supported
  var match = find(arr, function (obj) {
    return obj[prop] === value;
  });
  return arr.indexOf(match);
}
function findIndex ( arr , prop , value ) { // use native findIndex if supported if ( Array . prototype . findIndex ) { return arr . findIndex ( function ( cur ) { return cur [ prop ] === value ; } ) ; } // use `find` + `indexOf` if `findIndex` isn't supported var match = find ( arr , function ( obj ) { return obj [ prop ] === value ; } ) ; return arr . indexOf ( match ) ; }
Return the index of the matching object
@method
@memberof Popper.Utils
@argument {Array} arr
@argument prop
@argument value
@returns index or -1
Return the index of the matching object