coffeelint-advanced-colon-assignment-spacing/src/advanced_colon_assignment_spacing.coffee

Validate a spacing left and right of a colon assignment

module.exports = class AdvancedColonAssignmentSpacing

  rule:
    name: 'advanced_colon_assignment_spacing'
    level: 'warn'
    message: 'Colon assignment without proper spacing'
    spacing:
      left:
        min: 0
        max: 0
      right:
        min: 1
        max: null
    description: """
      <p>This rule checks to see that there is spacing before and
      after the colon in a colon assignment (i.e., classes, objects).
      The spacing amount is specified by
      spacing.left and spacing.right, respectively.
      A zero value means no spacing required.
      </p>
      <pre><code>
      #
      # If spacing.left and spacing.right is 1
      #

      # Good
      object = {spacing : true}
      class Dog
        canBark : true

      # Bad
      object = {spacing: true}
      class Cat
        canBark: false
      </code></pre>
      """

  tokens: [':']

  lintToken: (token, tokenApi) ->
    spacingAllowances = tokenApi.config[@rule.name].spacing
    previousToken = tokenApi.peek -1
    nextToken = tokenApi.peek 1

    getSpaceFromToken = (direction) ->
      switch direction
        when 'left'
          token[2].first_column - previousToken[2].last_column - 1
        when 'right'
          nextToken[2].first_column - token[2].first_column - 1

    checkSpacing = (direction) ->
      spacing = getSpaceFromToken(direction)
      # when spacing is negative, the neighboring token is a newline

      minSpaced = maxSpaced = false

      if spacing < 0
        minSpaced = maxSpaced = true
      else
        if spacingAllowances[direction].min?
          if spacing >= parseInt(spacingAllowances[direction].min)
            minSpaced = true
          else
            minSpaced = false
        else
          minSpaced = true


        if spacingAllowances[direction].max?
          if spacing <= parseInt(spacingAllowances[direction].max)
            maxSpaced = true
          else
            maxSpaced = false
        else
          maxSpaced = true

      isSpaced = minSpaced and maxSpaced

      [isSpaced, spacing]

    [isLeftSpaced, leftSpacing] = checkSpacing 'left'
    [isRightSpaced, rightSpacing] = checkSpacing 'right'

    if isLeftSpaced and isRightSpaced
      null
    else
      context:
        """
        Incorrect spacing around column #{token[2].first_column}.
        Expected left: #{spacingAllowances.left.min} - #{spacingAllowances.left.max}, right: #{spacingAllowances.right.min} - #{spacingAllowances.right.max}.
        Got left: #{leftSpacing}, right: #{rightSpacing}.
        """