1.4 Type Coercion & Equality

>>>

"text" == 'text'

true

>>>

"text" == "another text"

false

>>>

1 == "1"

true

Type coercion in effect. The string value is converted to a number before the comparison.

>>>

1 === "1"

false

>>>

null == undefined

true

Unexpected but nonetheless convenient. Using type coercion, a test for null will also match undefined values.

>>>

"" + 13

"13"

Type coercion can be forced explicitly. For example, a string result is forced by concatenating with an empty string. Note that the + operator has multiple meanings (more later).

>>>

String(true)

"true"

Remember those wrapper classes for the primitive types? These can be called as normal functions for type coercion to the corresponding primitive type.

>>>

The console allows you to interact with the course material and examples. Use the following keys:

<Enter> — Execute the code
<Shift + Enter> — Add line break
<Arrow-Up> — Previous command in history
<Arrow-Down> — Next command in history

A special logging function is also available:

print(value) — Prints a value to the console.
print(value, true) — Prints a debug version of a value.

Console Learner — An interactive JavaScript course.