JSFiddle - React, Tailwind, and code Playground
JavaScript
var arr1 = [], arr2 = [], arr3 = [],
mystring = "4|black|cat, 7|red|dog, 12|blue|fish";
mystring.replace(/(\d+)\|([^\|]+)\|([^,]+)/g, function ($0, $1, $2, $3) {
arr1.push($1);
arr2.push($2);
arr3.push($3);
});
alert(arr1);
alert(arr2);
alert(arr3);