String methods

Learn .length, .toUpperCase and .toLowerCase methods.

String methods

In Node.js text is held in the string type. You find how many characters a string has with the .length property: "Welcome".length evaluates to 7.

String methods are tools that operate on a string. .toUpperCase() upper-cases the letters, .toLowerCase() lower-cases them. For example "book".toUpperCase() returns "BOOK". Methods do not change the original string; they return a new one.

toUpperCase and toLowerCase

To upper-case a string's letters you use .toUpperCase(), to lower-case them .toLowerCase(). Both require an empty parenthesis () because they are method calls.

Important: methods do not modify the original string. const name = "Alex"; name.toUpperCase(); produces a new string "ALEX" but name stays "Alex". To keep the result you assign it to a new variable: const big = name.toUpperCase();.

Exercise Upper-case the city

The city variable is set to "Paris". Declare a new variable big and assign the result of city.toUpperCase() to it. Then print big with console.log. The output on a single line must be PARIS.

Show example solution

const city = "Paris";
const big = city.toUpperCase();
console.log(big);

Test yourself

What is const w = "Welcome"; w.length?
```
const w = "Welcome";
w.length
```
- 5
- 6
- 7
- 8
Show answer

7 — "Welcome" has 7 characters; length returns 7.

Write the toUpperCase call

const name = "Alex";
const big = name____;

Show answer

const name = "Alex";
const big = name.toUpperCase();

Match each method to its job

.length

Character count
.toUpperCase()

Upper-cases letters
.toLowerCase()

Lower-cases letters
"text"

String literal

Next lesson: String search

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