What are the differences of followings. when to use a one over the other?
zones: [Zone]
zones: [Zone!]
zones: [Zone]!
zones: [Zone!]!
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This can be summarised with this table of allowed values based on the definition:
values | [Zone] | [Zone!] | [Zone]! | [Zone!]! |
--------------------------------------------------------
null | ✔ | ✔ | X | X |
[] | ✔ | ✔ | ✔ | ✔ |
[null] | ✔ | X | ✔ | X |
["a","b"] | ✔ | ✔ | ✔ | ✔ |
["a",null,"c"] | ✔ | X | ✔ | X |
Most of the time, you will need to use [Zone!]! as it ensures that no null values will be found in your array.
Errorname
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Perfect!... also the answer is nicely organized. – Dulara Malindu Mar 23 '19 at 09:09
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what if I want to avoid [ ]? how is [ ] different from [null]? thanks – Antoni4 Jul 09 '19 at 23:36
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In a GraphQL shema, you cannot specify the required length, which means you cannot avoid an empty array ([]). – Errorname Jul 10 '19 at 07:13
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The difference between [] and [null] is that [] is an empty array, while [null] is an array with one element which is null. It's the same difference that can be seen in most languages. – Errorname Jul 10 '19 at 07:14