Using Variables

Add a variable and reference it in the book

Adding a new variable to the configuration file book.json lets you control the content from the configuration, either by setting values (like a product name) from the configuration, or by creating a condition for conditional rendering.

Variables are name-value pairs given as a quoted pair separated by a colon:

"name": "value"

Variables can be accessed in your content by referencing them using the template language:

{{ book.newVariableName }} 

{% if book.newVariableName == "New Value" %}
Content that will only be rendered if the new variable is equal to `"New Value"` in the book.json
{% endif %}

To add a variable:

1. Make sure you are on "branch: master" according to the "version" bar
2. Edit the "variables" section of book.json

book.json (before)

{
    "variables": {
        "edition": "master",
        "slides": false,
        "outputContent": [
            "content",
            "notes"
        ],
        "productName": "T Mobile Router"
    },
    "plugins": ["wrapclass", "addcssjs"],
    "pluginsConfig": {
        "addcssjs": {
            "css": ["https://fontlibrary.org/face/hk-grotesk"]
        }
    }
}

book.json (after)

{
    "variables": {
        "edition": "master",
        "slides": false,
        "outputContent": [
            "content",
            "notes"
        ],
        "productName": "T Mobile Router",
        "newVariableName": "New Value"
    },
    "plugins": ["wrapclass", "addcssjs"],
    "pluginsConfig": {
        "addcssjs": {
            "css": ["https://fontlibrary.org/face/hk-grotesk"]
        }
    }
}

Make sure that there is a comma before the variable you just added. Make sure there is no comma after the variable, if it is the last one. book.json must be valid JSON for your book to be created correctly, and Gitbook might not tell you that it isn't.

Variable names should never contain spaces.

Using variables in content

Using the value of a variable as text

Copy the bits in the source of this page between, but not including the ``` lines:

{{ book.variableName }}

Controlling whether a block of text is rendered

Copy the bits in the source of this page between, but not including the ``` lines:

{% if book.variableName in ['value1', 'value2'] %}
Insert the text you want to conditionally render here.
{% endif %}