How to substring method in React native? I tried all methods which are given below but none of the method worked.
substring, slice, substr
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1have you tried substring?Tim– Tim2018-07-11 07:46:39 +00:00Commented Jul 11, 2018 at 7:46
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I tried, it is crashing : TypeError: Cannot read property 'substring' of undefinedLuvnish Monga– Luvnish Monga2018-07-11 08:48:32 +00:00Commented Jul 11, 2018 at 8:48
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the data you are applying substring to is undefined. did you verify that?Aseem Upadhyay– Aseem Upadhyay2018-07-11 08:53:04 +00:00Commented Jul 11, 2018 at 8:53
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Again converted my string to string made me solution. Thank you.Luvnish Monga– Luvnish Monga2018-07-11 09:04:44 +00:00Commented Jul 11, 2018 at 9:04
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6 Answers
The substring method is applied to a string object.
The substring() method extracts the characters from a string, between two specified indices, and returns the new substring.
This method extracts the characters in a string between "start" and "end", not including "end" itself.
If "start" is greater than "end", this method will swap the two arguments, meaning str.substring(1, 4) == str.substring(4, 1).
If either "start" or "end" is less than 0, it is treated as if it were 0.
Note: The substring() method does not change the original string.
The way to use it is this:
var str = "Hello world!";
var res = str.substring(1, 4);
// res value is "ell"
3 Comments
Luvnish Monga
It's generating an error which is: TypeError: Cannot read property 'substring' of undefined.
Sternjobname
RN is just a library in JavaScript, so standard JS should work as expected. Can you supply your code in context so we can see if there's something causing the error?
SmoggeR_js
Probably you are referencing a undefined object. Check the variable you are trying to apply substring method is not undefined first
You can use it :
var str = "Hello world!"; var res = str.substring(0, 4); // output is Helloif you get from JSON
{item.name.substring(0, 4)}from text
this is text.substring(0, 5) // output is: this i
Comments
Method 1: With Variables
var str = "Demo String";
var res = str.substring(2, 5); //starts from 0
Method 2: With States Directly
<Text>{this.state.str.substring(0, 7)}</Text>
Comments
try
(obj.str).substring(1, 4);
1 Comment
Nick
Code only answers are discouraged. Please add some explanation as to how this solves the problem, or how this differs from the existing answers. From Review
Another alternative, you can make simple function. and then print in your jsx.
var number = "62857123456"
const slice = {
phone: (input: string = '') => {
let output = '';
// you can use substring, slice, substr
output = input.slice(2,14);
return output;
},
};
Finally, print on your jsx by calling the function that was created.
{slice.phone(number)}
Comments
I have faced the same situation For this the solution is place all js code in a function and call it externally
class AboutMe extends Component {
displayAboutMe(){
var data = this.props.getAboutMeQuery;
if(data.loading){
return(<div>Loading Books</div>)
}else{
var aboutMe = JSON.stringify(this.props.getAboutMeQuery.aboutme);
console.log(aboutMe);
var res = aboutMe.substring(12,453);
console.log(res);
}
}
render(){
this.displayAboutMe()
return (
<div id="profile-section"></div>
)}}
