I want to check is some text is in a string for instance i have a string
str = "car, bycicle, bus"
and I have another string
str2 = "car"
I want to check if str2 is in str.
I am a newbie in javascript so please bear with me :)
Regards
8 Answers
if(str.indexOf(str2) >= 0) {
...
}
Or if you want to go the regex route:
if(new RegExp(str2).test(str)) {
...
}
However you may face issues with escaping (metacharacters) in the latter, so the first route is easier.
2 Comments
switz
This should work perfectly.
indexOf returns the index of the beginning of str2 in str. returns -1 if it isn't in the array.Mark Bellamy
I like to use the != -1 variant. ---- if(str.indexOf(str2) != -1) {}
ES5
if(str.indexOf(str2) >= 0) {
...
}
ES6
if (str.includes(str2)) {
}
Comments
str.lastIndexOf(str2) >= 0; this should work. untested though.
let str = "car, bycicle, bus";
let str2 = "car";
console.log(str.lastIndexOf(str2) >= 0);
5 Comments
hughes
why use
lastIndexOf instead of just indexOf?
Doug Chamberlain
Just force of habit, i've gotten burned in the past using indexOf...lastIndexOf works the same as far as I know when there is only one instance of the string being looked for.
hughes
Interesting. What circumstances would case
indexOf to cause trouble?Doug Chamberlain
If you are looking for more than one way to skin this cat you could
var items = str.split(",") into an array then iterate through the array items checking for items[i] == str2....Doug Chamberlain
@Hughes, Not at all saying my way is right, and not something I've done in practice in a long time but,
var x = ',,' x.indexOf(x) == 0 x.lastIndexOf(x) == 1, you'd get two different results, and depending on the logic down the line you could have some issues.Use the builtin .includes() string method to check for the existence of sub-string.
It return boolean which indicates if the sub-string included or not.
const string = "hello world";
const subString = "world";
console.log(string.includes(subString));
if(string.includes(subString)){
// SOME CODE
}
Comments
Please use this :
var s = "foo";
alert(s.indexOf("oo") > -1);
3 Comments
Ram
How is this different from the accepted answer except that you use
> instead of >=?
darshankhamar
Ram, Both are the same!! If you will see conditions then both are indicating the same that whatever the value you get using "indexOf" function should be greater than or equal 0.
Ram
Both are the same that's what I meant. Please don't add a duplicate answer to the question instead upvote the existing answer if desired.
You can use this:
'a nice string'.includes('nice')
Comments
This function will tell you if the substring is in the string and how many times.
const textInString = (wordToFind, wholeText) => {
const text = new RegExp(wordToFind, 'g');
const occurence = wholeText.match(text) ?? [];
return [occurence.length > 0, occurence.length]
}
console.log(textInString("is", "This cow jumped over this moon"))Comments
If you just want to check substring in a string you can use indexOf but if you want to check if the word is in the string or not, the other answers might not work correctly for example:
str = "carpet, bycicle, bus"
str2 = "car"
What you want car word is found not car in carpet
if(str.indexOf(str2) >= 0) {
// Still true here
}
// OR
if(new RegExp(str2).test(str)) {
// Still true here
}
So you can improve the regex a bit to make it work
str = "carpet, bycicle, bus"
str1 = "car, bycicle, bus"
stringCheck = "car"
// This will false
if(new RegExp(`\b${stringCheck}\b`).test(str)) {
}
// This will true
if(new RegExp(`\b${stringCheck}\b`,"g").test(str1)) {
}
Stringmethods: developer.mozilla.org/en/JavaScript/Reference/Global_Objects/…