Pass a string into regex

Question

Consider the following:

 function filterFoods() {
   var foods = [
      {food: 'Bacon'}, {food: 'Butter'}, {food: 'Chicken'}, {food: 'Cocoa butter'},
      {food: 'Saussages'}, {food: 'Ham'}, {food: 'Duck'}, {food: 'Salmon'},
      {food: 'Fish'}, {food: 'Lamb'}, {food: 'Fries'}, {food: 'Tomatoes'},
      {food: 'Chicken'}, {food: 'Carrot'}, {food: 'Egg'}, {food: 'Avocado'},
      {food: 'Duck'}, {food: 'Hello'}, {food: 'Cheese'}, {food: 'Carrot'},
      {food: 'Potato'}, {food: 'Sweet Potato'}, {food: 'Pineapple'}, {food: 'Peanut'},
  ]
  return foods.filter(function(food) {
    return (/po/gi).test(food.food);
  });
}

console.log(
  filterFoods()
)

http://jsbin.com/gudekaruha/edit?js,console,output

I'm getting back [{food: 'Potato'},{food: 'Sweet Potato'}], which is what I want.

But I want to be able to pass something into the filterFoods function, and then into the regex, kind of like this:

 function filterFoods(query) {
   var foods = [
      {food: 'Bacon'}, {food: 'Butter'}, {food: 'Chicken'}, {food: 'Cocoa butter'},
      {food: 'Saussages'}, {food: 'Ham'}, {food: 'Duck'}, {food: 'Salmon'},
      {food: 'Fish'}, {food: 'Lamb'}, {food: 'Fries'}, {food: 'Tomatoes'},
      {food: 'Chicken'}, {food: 'Carrot'}, {food: 'Egg'}, {food: 'Avocado'},
      {food: 'Duck'}, {food: 'Hello'}, {food: 'Cheese'}, {food: 'Carrot'},
      {food: 'Potato'}, {food: 'Sweet Potato'}, {food: 'Pineapple'}, {food: 'Peanut'},
  ]
  return foods.filter(function(food) {
    return (/query/gi).test(food.food);
  });
}

console.log(
filterFoods('po')
)

But I'm getting back an empty array. Now correct me if I'm wrong but I think it's because I'm passing it in as a string, so how do I achieve this?

Thanks in advance

Answer 1

You need to use the RegExp() object.

return (new RegExp(query, 'gi')).test(food.food);