Pipe chaining in Angular - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is pipe chaining in Angular?

Pipe chaining means using multiple pipes one after another in a template expression to transform data step-by-step.

beginner

How do you write pipe chaining in Angular templates?

You write pipes separated by the pipe symbol (|), like: {{ value | pipe1 | pipe2 }}. The output of pipe1 becomes input for pipe2.

intermediate

Why use pipe chaining instead of one complex pipe?

Pipe chaining keeps transformations simple and reusable. Each pipe does one job, making code easier to read and maintain.

beginner

Example: What does {{ 'hello world' | uppercase | slice:0:5 }} output?

It outputs 'HELLO'. First, 'hello world' becomes 'HELLO WORLD' with uppercase pipe, then slice extracts first 5 characters.

intermediate

Can pipes in a chain accept parameters? How?

Yes. Each pipe can have its own parameters after a colon, like {{ value | pipe1:param1 | pipe2:param2:param3 }}.

What symbol is used to chain pipes in Angular templates?

A :

B &

C ;

D |

The pipe symbol (|) is used to chain pipes, passing the output of one pipe as input to the next.

In pipe chaining, which pipe runs first?

A The first pipe in the chain

B The last pipe in the chain

C All pipes run simultaneously

D Depends on the pipe parameters

The first pipe runs first, transforming the original value, then its output goes to the next pipe.

What will {{ 123.456 | number:'1.0-2' | currency }} do?

A Only format decimals, ignore currency

B Add currency symbol, then format decimals

C Format number with 2 decimals, then add currency symbol

D Throw an error

The number pipe formats decimals first, then currency pipe adds the currency symbol.

Can you chain custom pipes with built-in pipes?

A Only custom pipes can be chained

B Yes, any pipes can be chained

C No, only built-in pipes can be chained

D Only pipes without parameters can be chained

Angular allows chaining any pipes, built-in or custom, as long as they follow pipe rules.

What happens if a pipe in the chain returns null?

A The next pipe receives null as input

B The chain stops and shows an error

C The chain skips that pipe

D Angular replaces null with empty string automatically

The output of each pipe is passed as input to the next, even if it is null.

Explain how pipe chaining works in Angular templates and why it is useful.

Think about how you might prepare food in steps, each step changing the dish a bit.

Describe how to pass parameters to pipes in a chain and give an example.

Parameters customize how each pipe transforms the data.