Object Literals

Objects in Textwire are very similar to JavaScript object with key-value pairs. Example:

{{ person = {"name": "John", "age": 25} }}

You can also use key names without quotes if your keys are valid identifiers:

{{ person = { name: "John", age: 25 } }}

You can access values in an object by using a key. Example:

{{ user = {age: 25, name: {first: "Anna", last: "Cho"}} }}

<ul>
    <li>First name: {{ user.name.first }}</li> {{-- "Anna" --}}
    <li>Last name: {{ user.name.last }}</li> {{-- "Cho" --}}
    <li>Age: {{ user.age }}</li> {{-- 25 --}}
</ul>

You can also use an index expression with the key as a string:

{{ hero = { name: 'Skirk', 'release-version': '5.7' } }}

{{ hero['name'] }}             {{-- Skirk --}}
{{ hero['release-version'] }}  {{-- 5.7 --}}

This is useful for keys that are not valid identifiers, such as release-version.

Uppercase-First Properties

Property keys that start with an uppercase letter can be accessed in lowercase, and vice versa. If you are passing an object like user: User that has a Name field, you can access it as {{ user.name }} or {{ user.Name }}, both work. The same applies to nested properties, like {{ user.name.first }} and {{ user.Name.First }}:

{{ user = {Name: {First: "Anna", Last: "Cho"}} }}

<li>First name: {{ user.name.first }}</li>  {{-- "Anna" --}}
<li>Last name: {{ user.Name.First }}</li>  {{-- "Anna" --}}

It only works for the first letter of the property.

First character case-insensitivity in field access

Field name matching ignores case differences in the first character. This means {{ user.name.first }} and {{ user.Name.First }} resolve to the same result.

Keys must be identifiers or strings

Unquoted keys have to be valid identifiers. If a key contains characters like - or starts with a number, wrap it in quotes. Example:

{{ user = { name: "John", "first-name": "Johnny", "1st": true } }}

Dot and bracket access

Use obj.key or obj['key'] to read a value. Bracket access takes a string key. Use dot notation to assign values, for example user.name = "Anna".

Safe accessing

You can use the get() function to safely access object properties without worrying about errors. Example:

{{ user = {age: 25, name: {first: 'Anna', last: 'Cho'}} }}
{{ user.get('name.first') }}

Only exported fields are converted

Textwire automatically converts Go structs to objects, but only exported fields are converted. Since Go doesn't export fields that start with lowercase letters, Textwire cannot access them. Make sure to capitalize field names if you want them available in your templates.

Accessing missing object properties returns nil

Similar to arrays, trying to access a property that doesn't exist on an object returns nil rather than throwing an error. However, this only applies to the first undefined property—attempting to access a property on nil itself will result in an error.

Sorted keys when printed

Objects in Textwire maintain the order of keys in alphabetical order when printed or in JSON string if you do {{ myObj.json() }}.

Shorthand Property Notation

Similar to objects in JavaScript, you can use shorthand property notation to define an object.

{{ name = "John"; age = 25 }}
{{ person = { name, age } }}

No circular references

Assigning an array or object into itself, directly or through nested values, is an error. The assignment is rejected and the template fails with an error message.

{{ a = [1]; a[0] = a; a }}

{{ b = {x: 1}; b.y = b; b }}