textlint-rule-no-dead-relative-link

This is a textlint rule that validate links in markdown documents. It does the following

• It ignores external link. The RegExp used to filter out such links is /^[a-z][a-z0-9+.-]*:/i
• For all relative links, it checks that there is a file specified by the link. The relative links are resolved relative to the file containing the link.
• For all relative links with anchors or just anchor within the same file, it checks that the anchor exists. It treats anchor links to markdown documents the same way as github does i.e. the rule uses github-slugger to do validation.

Installation

• Since this is a textlint rule, first install textlint by following the textlint getting started guide.
• This rule is available as an npm package and can be installed using
  • npm install --save-dev textlint-rule-no-dead-relative-link
    or
  • yarn add --dev textlint-rule-no-dead-relative-link and then yarn install

Usage

If you are unfamiliar with textlint then refer to configuring textlint for textlint configuration details.

Add one of the following to .textlintrc file

• without any options

{
    "rules": {
        "no-dead-relative-link": true
    }
}

or

• with options

{
    "rules": {
        "no-dead-relative-link": {
            "resolve-as-markdown": "[.html]"
        }
    }
}

To use it via command line arguments

textlint --rule textlint-rule-no-dead-relative-link README.md

Options

resolve-as-markdown

This option takes an array of file extension values and treats files with those extensions as if they are markdown files.

For e.g. With the following configuration

{
    "rules": {
        "no-dead-relative-link": {
            "resolve-as-markdown": [".html"]
        }
    }
}

and [README](README.html) as input, this rule will check for the existence of README.md file.

route-map

Use this option when relative links need to be validated using an alternate file path.

This option takes an array of source and destination pairs. The source value is a Regex, and the destination value is a String that can include capture groups from the source using the $ notation.

For e.g. With the following configuration

{
    "rules": {
        "no-dead-relative-link": {
            "route-map": [
                {
                    "source": "^../javadocs/(\\d+\\.\\d+\\.\\w+)", 
                    "destination": "../../static/javadocs/$1"
                }
            ]
        }
    }
}

and ../javadocs/1.0.x/overview-summary.html as the link being checked, this rule checks for the existence of the overview-summary.html file at ../../static/javadocs/1.0.x/overview-summary.html.

route-map Ordering

Ensure each route-map pair is specific because the route-map option will validate relative links using the first matching regex found in the configuration.

For e.g. With the following configuration

{
    "rules": {
        "no-dead-relative-link": {
            "route-map": [
                {
                    "source": "../../javadocs/",
                    "destination": "../website/static/javadocs/"
                },
                {
                    "source": "../javadocs/1.0.x/",
                    "destination": "../../static/javadocs/1.0.x/"
                }
            ]
        }
    }
}

and ../../javadocs/1.0.x/overview-summary.html as the link being checked, this rule checks for the existence of the overview-summary.html file at the first destination ../website/static/javadocs/1.0.x/overview-summary.html instead of the second destination ../../static/javadocs/1.0.x/overview-summary.html.