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Template Expression Operators Copy Edit

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Waterloo ENGL 210 J Student 
Changed order of text in pipe operator to introduce pipe operator 
Changed word choice/word location in pope operator 
Added : before examples to keep consistent
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amandaegraham 2016-07-19 23:43:50 -04:00 committed by Naomi Black
parent 7e1dba64eb
commit d0811714d5
1 changed files with 9 additions and 9 deletions
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18
public/docs/ts/latest/guide/template-syntax.jade
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@ -1401,11 +1401,11 @@ h3#aliasing-io Aliasing input/output properties
:marked
<a id="pipe"></a>
### The pipe operator ( | )
Pipes are simple functions that accept an input value and return a transformed value.
The result of an expression might require some transformation before we’re ready to use it in a binding. For example, we might want to display a number as a currency, force text to uppercase, or filter a list and sort it.
Angular [pipes](./pipes.html) are a good choice for small transformations such as these.
Pipes are simple functions that accept an input value and return a transformed value.
They're easy to apply within template expressions, using the **pipe operator (`|`)**:
Angular [pipes](./pipes.html) are a good choice for small transformations such as those listed above.
Pipe operators are easy to apply within template expressions, using the **pipe operator (`|`)**:
+makeExample('template-syntax/ts/app/app.component.html', 'pipes-1')(format=".")
:marked
The pipe operator passes the result of an expression on the left to a pipe function on the right.
@ -1413,7 +1413,7 @@ h3#aliasing-io Aliasing input/output properties
We can chain expressions through multiple pipes:
+makeExample('template-syntax/ts/app/app.component.html', 'pipes-2')(format=".")
:marked
And we can also [apply parameters](./pipes.html#parameterizing-a-pipe) to a pipe:
We can also [apply parameters](./pipes.html#parameterizing-a-pipe) to a pipe:
+makeExample('template-syntax/ts/app/app.component.html', 'pipes-3')(format=".")
block json-pipe
@ -1421,7 +1421,7 @@ block json-pipe
The `json` pipe is particularly helpful for debugging our bindings:
+makeExample('template-syntax/ts/app/app.component.html', 'pipes-json')(format=".")
:marked
The generated output would look something like this
The generated output would look something like this:
code-example(language="json").
{ "firstName": "Hercules", "lastName": "Son of Zeus",
"birthdate": "1970-02-25T08:00:00.000Z",
@ -1433,7 +1433,7 @@ block json-pipe
### The safe navigation operator ( ?. ) and null property paths
The Angular **safe navigation operator (`?.`)** is a fluent and convenient way to guard against null and undefined values in property paths.
Here it is, protecting against a view render failure if the `currentHero` is null.
Here it is used to protect against against a view render failure if the `currentHero` is null:
+makeExample('template-syntax/ts/app/app.component.html', 'safe-2')(format=".")
block dart-safe-nav-op
@ -1446,10 +1446,10 @@ block dart-safe-nav-op
+makeExample('template-syntax/ts/app/app.component.html', 'safe-1')(format=".")
:marked
The view still renders but the displayed value is blank; we see only "The title is" with nothing after it.
That is reasonable behavior. At least the app doesn't crash.
That is reasonable a behavior. At least the app doesn't crash.
Suppose the template expression involves a property path, as in this next example
where we’re displaying the `firstName` of a null hero.
Suppose the template expression involves a property path, as seen in this next example
where we’re displaying the `firstName` of a null hero:
code-example(language="html").
The null hero's name is {{nullHero.firstName}}