jekyll_begin

Published 2020-10-03. Last modified 2023-05-23.
Time to read: 1 minutes.

This page is part of the jekyll_plugins collection.

jekyll_begin_end

This Jekyll plugin defines the following filters:

begins_with – returns true if a string starts with a given substring.
does_not_begin_with – returns false if a string starts with a given substring.
ends_with – returns true if a string ends with a given substring.
does_not_end_with – returns false if a string ends with a given substring.
append_suffix_if_does_not_start_with – appends a suffix to the string if the string does not start with a substring.

Installation

Add the following highlighted line to your Jekyll project's Gemfile, within the jekyll_plugins group:

Shell

group :jekyll_plugins do 
  gem 'jekyll_begin_end'
end

And then execute:

Shell

$ bundle

Syntax

Important: the name of each of these filters must be followed by a colon (:). If you fail to do that an error will be generated and the Jekyll site building process will halt. The error message looks something like this:

Liquid Warning: Liquid syntax error (line 285): Expected end_of_string but found string in "{{ lines | begins_with 'blah' | xml_escape }}" in /some_directory/some_files.html Liquid Exception: Liquid error (line 285): wrong number of arguments (given 1, expected 2) in /some_directory/some_file.html Error: Liquid error (line 285): wrong number of arguments (given 1, expected 2).

Examples

begins_with

Shell

{% assign url = "https:/asdf.com" %}
{% assign isAbsolute = url | begins_with: 'http' %}

Shell

{% assign url = "https:/asdf.com" %}
{% assign isHttp = url | begins_with: 'http' %}
{% if isHttp %}
  <p>Absolute</p>
{% else %}
  <p>Relative</p>
{% endif %}

does_not_begin_with

Shell

{% assign url = "https:/asdf.com" %}
{% assign isRelative = url | does_not_begin_with: 'http' %}

Shell

{% assign url = "https:/asdf.com" %}
{% assign isRelative = url | does_not_begin_with: 'http' %}
{% if isRelative %}
  <p>Relative</p>
{% else %}
  <p>Absolute</p>
{% endif %}

ends_with

Shell

{% assign url = "https:/asdf.com" %}
{% assign isDotCom = url | ends_with: '.com' %}

Shell

{% assign url = "https:/asdf.com" %}
{% assign isDotCom = url | ends_with: '.com' %}
{% if isDotCom %}
  <p>.com found</p>
{% else %}
  <p>Not a .com</p>
{% endif %}

does_not_end_with

Shell

{% assign url = "https:/asdf.com" %}
{% assign isNotDotCom = url | does_not_end_with: '.com' %}

Shell

{% assign url = "https:/asdf.com" %}
{% assign isNotDotCom = url | does_not_end_with: '.com' %}
{% if isNotDotCom %}
  <p>Not a .com</p>
{% else %}
  <p>.com found</p>
{% endif %}

append_suffix_if_does_not_start_with

This filter was created to make asset reloading work better.

Given a portion of _layouts/default.html that looks like this:

Shell

{% assign csses = page.css | default: layout.css %}
{% assign nowMillis = site.time | date: '%s' %}
{% assign suffix = '?v=' | append: nowMillis %}
{% for css in csses %}
  <link rel="stylesheet" href="{{ css | append_suffix_if_does_not_start_with: 'http', suffix }}" type="text/css">
{% endfor %}

And given index.html with front matter that looks like this:

Shell

---
css: [
  https://cdnjs.cloudflare.com/ajax/libs/jquery-modal/0.9.1/jquery.modal.min.css,
  /order/order.css
]
---

The following is generated. Note that the suffix s?v=1612879301 in only applied to the relative URL for order.css.

Shell

<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/jquery-modal/0.9.1/jquery.modal.min.css" type="text/css">
<link rel="stylesheet" href="/order/order.css?v=1612879301" type="text/css">