Property binding with square brackets in Angular - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is property binding in Angular?

Property binding in Angular lets you set the value of an element's property using data from the component. It uses square brackets to connect the property to a component variable.

beginner

How do you bind a component variable 'title' to an HTML element's 'textContent' property?

Use square brackets like this: <h1 [textContent]="title"></h1>. This sets the element's text content to the value of 'title'.

intermediate

Why use property binding instead of interpolation {{}} for setting element properties?

Property binding updates the actual DOM property directly, which is better for non-text properties like disabled, src, or value. Interpolation works for text content but does not update DOM properties directly.

intermediate

What happens if you use property binding with square brackets on a native HTML attribute?

Angular sets the DOM property, not the attribute. For example, [disabled]="true" disables the element by setting its property, which is more reliable than setting the attribute.

intermediate

Can you bind to custom properties of Angular components using square brackets?

Yes! You can bind to @Input() properties of child components using square brackets, passing data from parent to child components.

What syntax does Angular use for property binding?

A Square brackets around the property name

B Double curly braces {{}}

C Parentheses around the property name

D Angle brackets <>

Angular uses square brackets [] around the property name to bind it to a component variable.

Which of these is a correct example of property binding to set an image source?

A <img src="imageUrl">

B <img [src]="imageUrl">

C <img (src)="imageUrl">

D <img {src}="imageUrl">

Property binding uses square brackets: sets the src property to the component's imageUrl.

What does Angular update when using property binding?

A The event listeners of the element

B The HTML attribute of the element

C The CSS style of the element

D The DOM property of the element

Property binding updates the DOM property, which controls the element's behavior and appearance.

Which is the best use case for property binding over interpolation?

A Setting the disabled state of a button

B Adding spaces between words

C Setting text inside a paragraph

D Changing font color

Property binding is best for properties like 'disabled' that control element behavior, not just text content.

Can property binding be used to pass data to child components?

A Only with event binding

B No, only for HTML elements

C Yes, via @Input() properties

D Only with interpolation

Property binding can pass data to child components through their @Input() properties.

Explain how property binding with square brackets works in Angular and why it is useful.

Think about how Angular connects component variables to HTML element properties.

Describe how you would use property binding to disable a button based on a component variable.

Consider how the button's disabled property changes with the variable.