Alternative to eval for converting a string to an object

Question

I have a function that is using eval to convert a string with an expression to an object based on the parameter.

let indexType = ["Mac", "User", "Line", "Mask", "Ip", "Location"]

const filterIndex = (item) => {
  filteredIndexSearch = []
  eval(`search${item}`).forEach((e) => filteredIndexSearch.push(searchData[e.key]))
}

filterIndex(indexType[searchTotal.indexOf(Math.max(...searchTotal))])

searchData is an array that returns values based on the user input.

searchTotal is an array with the length of each search{item} array.

The filterIndex function takes the highest value from the searchData array and corresponds it to the indexType array, then use eval to convert the string to an object to pass the value to the filteredIndexSearch array.

What would be a better alternative to eval?

EDIT

To add more information on what this does:

searchData = [
  [
    {
      key: 1,
      data: "0123456789101"
    },
    {
      key: 1,
      data: "John Smith"
    }
  ],
  [
    {
      key: 2,
      data: "0123456789102"
    },
    {
      key: 2,
      data: "Jane Smith"
    },
  ]
]

const search = (data, key, container) => {
  if (!data) data = "";
  if (data.toLowerCase().includes(string)) {
    container = container[container.length] = {
      key: key,
      data: data
    }
  }
}

const returnSearch = () => {
  for (let i = 0; i < searchData.length; i++) {
    search(searchData[i][0].data, searchData[i][0].key, searchMac)
    search(searchData[i][1].data, searchData[i][1].key, searchUser)
  }
}

returnSearch()

The data is incomplete, but hopefully conveys what I'm trying to do.

search will take the user input, and store the information in the corresponding array. If I input "Jo", it will return the searchUser array with only the "John Smith" value and all the other values with the same key. Inputting "102" returns the searchMac with the "0123456789102" value and all other values with the same key.

At the end of the day. I just want to convert search${parameter} to an object without using eval.

Answer 1

Move your global arrays into an object.

Somewhere it appears that you're defining the arrays, something like:

searchMac = [...];
searchUser = [...];
...

Instead of defining them as individual arrays, I'd define them as properties in an object:

searchIndices.Mac = [...];
searchIndices.User = [...];
...

Then, instead of using eval, your can replace your eval().forEach with searchIndices[item].forEach.

If the order of your search isn't important, your can instead loop through the keys of searchIndices:

Object.keys(searchIndices).forEach(item => {
  searchIndices[item].forEach(...);
});

This ensures that if you ever add or drop an entry in searchIndices, you won't miss it or accidentally error out on an undefined search index.