what does !Array.<string>= mean in angular?

Question

Been reading the AngularJS documentation and found some param type

!Array.<string>=

What does this mean? any answer would clear things up.

You can see it in the code - That is an type indicator for the parameter saying it is expecting an array of string values as the said parameter — Arun P Johny
– Arun P Johny, Commented Mar 16, 2016 at 3:41
@ArunPJohny Well why the !Array.<string>? is '!' an inverse? — Reyn
– Reyn, Commented Mar 16, 2016 at 3:45

Jonathan Lonowski · Accepted Answer · 2016-03-16 05:41:49Z

2

The operators are from Google Closure's Type Expressions.

! identifies the type as "Non-nullable."
<...> identifies the type(s) of an object/collection's contents.
= identifies the parameter as "Optional."

So, in the case of angular.module():

No argument has to be given for requires.
When it is given, it cannot be null and must be an Array containing only string values.

angular.module('Foo');               // valid arguments
angular.module('Foo', null);         // not valid
angular.module('Foo', ['Bar']);      // valid
angular.module('Foo', [false]);      // not valid
angular.module('Foo', function(){}); // valid

edited Mar 16, 2016 at 5:41

answered Mar 16, 2016 at 4:27

Jonathan Lonowski

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2 Comments

Reyn Over a year ago

but what about the Array.<string> @JonathanLonowski? is the <string> the type??

Jonathan Lonowski Over a year ago

The <...> represents the type of the contents/elements/etc., so Array<string> is an "array of strings."

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