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5 string methods in JavaScript.

murtajaziad profile image Murtaja Ziad Originally published at blog.murtajaziad.xyz on ・2 min read

Strings are useful for holding data that can be represented in text form, and here’s 5 methods for them.


1. includes()

includes() method determines whether one string may be found within another string, returning true or false.

const sentence = "The quick brown fox jumps over the lazy dog.";

const word = "fox";

console.log(
  `The word "${word}" ${
    sentence.includes(word) ? "is" : "is not"
  } in the sentence.`
); // The word "fox" is in the sentence.
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2. replace()

replace() method returns a new string with some or all matches of a pattern replaced by a replacement. The pattern can be a string or a RegExp, and the replacement can be a string or a function to be called for each match. If pattern is a string, only the first occurrence will be replaced.

const p =
  "The quick brown fox jumps over the lazy dog. If the dog reacted, was it really lazy?";
const regex = /dog/gi;

console.log(p.replace(regex, "ferret")); // The quick brown fox jumps over the lazy ferret. If the ferret reacted, was it really lazy?

console.log(p.replace("dog", "monkey")); // The quick brown fox jumps over the lazy monkey. If the dog reacted, was it really lazy?
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3. split()

split() method divides a String into an ordered list of substrings, puts these substrings into an array, and returns the array.

const str = "The quick brown fox jumps over the lazy dog.";

const words = str.split(" ");
console.log(words[3]); // fox

const chars = str.split("");
console.log(chars[8]); // k
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4. startsWith()

startsWith() method determines whether a string begins with the characters of a specified string, returning true or false as appropriate.

const str = "Saturday night plans";

console.log(str.startsWith("Sat")); // true
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5. trim()

trim() method removes whitespace from both ends of a string. Whitespace in this context is all the whitespace characters (space, tab, no-break space, etc.) and all the line terminator characters (LF, CR, etc.).

const greeting = " Hello world! ";

console.log(greeting); // " Hello world! "
console.log(greeting.trim()); // "Hello world!"
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