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postcss-message-helpers

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Readme

postcss-message-helpers

PostCSS helpers to throw or output GNU style messages.

This modules offers you some function to throw or just output messages with GNU style: sourcefile:lineno:column: message

Installation

$ npm install postcss-message-helpers

var messageHelpers = require("postcss-message-helpers")

Usage

`var fnValue = messageHelpers.try(fn, source)`

Execute fn an return the value. If an exception is thrown during the process, the exception will be catched, enhanced from source & re-throw.

`var sourceMessage = messageHelpers.message(message, source)`

Returns a message like sourcefile:lineno:column: message.
source should be a postcss source object from a node.

`var source = messageHelpers.source(source)`

Returns sourcefile:lineno:column for a given source postcss object.

Example

// dependencies
var fs = require("fs")
var postcss = require("postcss")
var messageHelpers = require("postcss-message-helpers")

// css to be processed
var css = fs.readFileSync("input.css", "utf8")

// process css
var output = postcss()
  .use(function(styles) {
    styles.eachDecl(function transformDecl(decl) {
      // will catch, adjust error stack, line, column & message (gnu style) then re-throw
      messageHelpers.try(function IwillThrow() {
        if (decl.value.indexOf("error(") > -1) {
          throw new Error("error detected: " + decl.value)
        }
      }, decl.source)

      // will output a gnu style warning
      if (decl.value.indexOf("warning(") > -1) {
        console.warning(messageHelpers.message("warning: " + decl.value, decl.source))
      }
    })
  })
  .process(css)
  .css

Checkout tests for more examples.

Contributing

Work on a branch, install dev-dependencies, respect coding style & run tests before submitting a bug fix or a feature.

$ git clone https://github.com/postcss/postcss-message-helpers.git
$ git checkout -b patch-1
$ npm install
$ npm test

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