Use dynamic variable with array map react native

Question

I'm trying to print an Array whose name is being calculated based on selected value. e.g.

const ANotes = ["B", "C", "D"];
const keyNotes = MyNotes[selected] + "Notes"; //value is ANotes

Trying to render it as:

<View>
        {{keyNotes}.map((item, key)=>(
         <Text key={key} 
          //style={styles.TextStyle} 
          //onPress={ this.SampleFunction.bind(this, item) }
          > { item } , </Text>)
        )}
      </View>

When I try to render it in View in my Component it gives error. I'm new to React Native so not able to figure this one. I want the output to show B, C, D in the App.

It gives error: TypeError: undefined is not a function.

Moshe Sommers · Answer 1 · 2020-06-10T13:33:10.343

0

You cant use a string value to access a variable in the local scope without it being attached to some object or array check out this SO for some solutions

Seems you're using functional component if you switch to a class component you can then access it with this[keyNotes]

<View>
     {this[keyNotes].map((item)=><Text key={item}> {item}Notes,  </Text>)} 
</View>

Here's a working sandbox (I'm using react not react-native so I changed to dom eelments)

edited Jun 10 '20 at 13:33

answered Jun 09 '20 at 20:18

Moshe Sommers

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11

keyNotes is the selected value that holds the string ANotes. I used this as an example. – pulkitgulati Jun 10 '20 at 07:04
What do you mean the "string ANotes"? ANotes is an array. And what's MyNotes? – Moshe Sommers Jun 10 '20 at 11:42
MyNotes[selected] evaluates to "A" which makes keyNotes evaluate to "ANotes". It's mentioned in the code snippet comment part. – pulkitgulati Jun 10 '20 at 12:41
So KeyNotes is the string 'ANotes'? – Moshe Sommers Jun 10 '20 at 12:51
Yes. So if I use keyNotes to fetch array values of ANotes. What should be the exact syntax? – pulkitgulati Jun 10 '20 at 13:09
Oh I don't believe that's possible without attaching it to an object or array and accesing it like so `ArrayName[KeyNotes]` check this out https://stackoverflow.com/a/56926156/7645069 for some other solutions – Moshe Sommers Jun 10 '20 at 13:12
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/215675/discussion-between-moshe-sommers-and-pulkitgulati). – Moshe Sommers Jun 10 '20 at 13:15

Use dynamic variable with array map react native

1 Answers1