String manipulation types (Uppercase, Lowercase) in Typescript - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the toUpperCase() method do in TypeScript strings?

It converts all the letters in a string to uppercase letters. For example, "hello" becomes "HELLO".

beginner

What is the purpose of the toLowerCase() method in TypeScript?

It changes all the letters in a string to lowercase letters. For example, "WORLD" becomes "world".

beginner

How would you convert the string "TypeScript" to uppercase in TypeScript?

Use the code: "TypeScript".toUpperCase(). This returns "TYPESCRIPT".

beginner

How do you convert a string to lowercase in TypeScript?

Call the toLowerCase() method on the string. For example, "HELLO".toLowerCase() returns "hello".

intermediate

Are toUpperCase() and toLowerCase() methods destructive (do they change the original string)?

No, strings in TypeScript are immutable. These methods return a new string with the changes, leaving the original string unchanged.

What will "hello world".toUpperCase() return?

A "HELLO world"

B "hello world"

C "Hello World"

D "HELLO WORLD"

The toUpperCase() method converts all letters to uppercase.

Which method converts a string to all lowercase letters?

A toLower()

B toUpperCase()

C toLowerCase()

D lowerCase()

toLowerCase() is the correct method to convert strings to lowercase.

If you run let s = "Test"; s.toUpperCase(); console.log(s);, what is printed?

A "Test"

B "TEST"

C "test"

D Error

Strings are immutable, so s.toUpperCase() returns a new string but does not change s.

What type of value do toUpperCase() and toLowerCase() return?

A An array

B A new string

C A number

D Undefined

Both methods return a new string with the case changed.

Which of these is NOT true about toUpperCase() and toLowerCase()?

A They change the original string.

B They return a new string.

C They work on string values.

D They do not modify the original string.

Strings are immutable, so these methods do not change the original string.

Explain how to convert a string to uppercase and lowercase in TypeScript. Include what happens to the original string.

Think about string immutability and method names.

Describe a real-life example where converting text to uppercase or lowercase might be useful in a program.

Consider how computers treat letters differently by case.