Filter Array of Objects based on input field in React

Question

Got in a rather troublesome situation I have an array of objects

[
   {
     "title":"placeholder",
     "text":"placeholder"
   },
   {
     "title":"test",
     "text":"placeholder"
   },
   {
     "title":"javascript",
     "text":"placeholder"
   }
]

I am displaying them in a div,but thats not important I got an input field which users should type in title's and as they type the array should only show matching object. Inputing java would show the javascript titled object

I need to somehow change the array so it doesnt display anything but the entered title and if the input is empty shows the whole array

I am using React but i can only use hooks So i copy the json

var [arrayOfObjects, setArray] = useState(Json)

the Json is imported from a local file arrayOfNotes is the array that i need to change pointing out so its easier to understand

ty in advance

Welcome to stackoverflow! Have you gotten any further than this? Do you have state for your input text value? — azium
– azium, Commented Nov 16, 2019 at 17:32
well i have the whole thing done but this filter function, i can either either copy the input value into a variable with a simple a=docume.getelbyid().value, or i can set the input value into a state, i am ok with that,my problem maybe explained in a better way: for example having 2 objects with titles "javascript" and "javasssssscript", i can get it to show 1 of them by entering "javasc" or "javass" but if the user deletes the "s" from "javass" and gets "javas" i still have only 1 showing,cant get back the other 1 — Marko Zivanovic
– Marko Zivanovic, Commented Nov 16, 2019 at 17:41

azium · Accepted Answer · 2019-11-16 18:05:52Z

17

The array filter method is what you're looking for.

Here's what your component might looks like.

const List = ({ data }) => {
  const [value, setValue] = useState('')

  return (
    <div>
      <input 
        type="text"
        value={value} 
        onChange={e => setValue(e.target.value)} 
      />

      {data
        .filter(item => {
          if (!value) return true
          if (item.title.includes(value) || item.text.includes(value)) {
            return true
          }
        })
        .map(item => (
          <div>
            <h1>{item.title}</h1>
            <p>{item.text}</p>
          </div>
        ))
      }
    </div>
  )
}

And you pass your json data to that component

<List data={Json} />

Here's a working example of the above code

edited Nov 16, 2019 at 18:05

answered Nov 16, 2019 at 18:00

azium

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Comments

dmigo · Accepted Answer · 2019-11-16 18:18:47Z

1

You didn't share your component so I'll assume you know how to get the input value and call the corresponding variable input, besides you have your original array, from your example I judge it is called Json.

Then you can filter your value as follows:

const [arrayOfObjects, setArray] = useState(Json);
const filteredArray = input ?
    originalArray.filter(item => item.title.includes(input) :
    originalArray;

So that later you can render the filteredArray as follows:

<ul>
  {filteredArray.map(item => (<li>{item.title}</li>))}
</ul>

edited Nov 16, 2019 at 18:18

answered Nov 16, 2019 at 17:43

dmigo

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10 Comments

azium Over a year ago

You don't necessarily need a filteredArray state. You could just filter it directly in render

dmigo Over a year ago

True if you always have access to the initial state of Json. Not so if this Json comes for a server request, or such.

azium Over a year ago

It doesn't matter where it comes from. The point is to display the filtered results, and for that you don't ever need a second piece of state. You just need to call filter in render

dmigo Over a year ago

But how will you get to the original state after the user enters some value and erases it?

azium Over a year ago

There is only ever original state, that's my point. In fact you don't even need any state for the array to do what the OP is asking, you could just as well do it by filtering props

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