canonical/node_modules/css-lint/lib/rules/shorthand-values.js

Canonical code style linter and formatter for JavaScript, SCSS and CSS.

'use strict';

var helpers = require('../helpers');

var shortVals = [
  'border-color',
  'border-radius',
  'border-style',
  'border-width',
  'margin',
  'padding'
];

var condenseToOne = function (value, allowed) {
  if (allowed.indexOf(1) !== -1 && value.length > 1) {
    for (var i = 1; i < value.length; i++) {
      if (value[i] !== value[0]) {
        return false;
      }
    }
    return true;
  }
  return false;
};

var condenseToTwo = function (value, allowed) {
  if (allowed.indexOf(2) !== -1 && value.length > 2) {
    if ((value[0] === value[2] && value[1] === value[3]) || (value[0] === value[2] && !value[3] && value[0] !== value[1])) {
      return true;
    }
  }
  return false;
};

var condenseToThree = function (value, allowed) {
  if (allowed.indexOf(3) !== -1 && value.length > 3) {
    if (value[1] === value[3] ) {
      return true;
    }
  }
  return false;
};

module.exports = {
  'name': 'shorthand-values',
  'defaults': {
    'allowed-shorthands': [1, 2, 3]
  },
  'detect': function (ast, parser) {
    var result = [];

    ast.traverseByType('declaration', function (declaration) {
      var isShorthandProperty = false,
          property;

      declaration.traverse(function (item) {

        if (item.is('property')) {
          item.traverse(function (child) {
            // check if the property is a possible shorthand property
            if (shortVals.indexOf(child.content) !== -1) {
              isShorthandProperty = true;

              // store a reference to the property for our error
              property = shortVals[shortVals.indexOf(child.content)];
            }
          });
        }

        if (isShorthandProperty) {
          var value = [];

          if (item.is('value')) {
            var node = item.content,
                fullVal = '';

            // Build each value into an array of strings with value and type
            node.forEach(function (val) {
              // add to our value string depending on node type
              if (val.is('dimension')) {
                val.forEach(function (el) {
                  fullVal += el.content;
                });
              }

              else if (val.is('operator') || val.is('ident') || val.is('number') || val.is('unaryOperator')) {
                fullVal += val.content;
              }

              else if (val.is('variable')) {
                val.forEach(function (el) {
                  fullVal += '$' + el.content;
                });
              }

              else if (val.is('space')) {
                // This is a non value character such as a space
                // We want to start another value here
                value.push(fullVal);

                // reset the value string for the next iteration
                fullVal = '';
              }
            });
            if (fullVal !== '') {
              // The last dimension in a value will not be followed by a character so we push here
              value.push(fullVal);

              if (value.length <= 4 && value.length >= 1) {
                var output = [];

                // check which values can condense
                if (condenseToOne(value, parser.options['allowed-shorthands'])) {
                  output = [value[0]];
                }
                else if (condenseToTwo(value, parser.options['allowed-shorthands'])) {
                  output = [value[0], value[1]];
                }
                else if (condenseToThree(value, parser.options['allowed-shorthands'])) {
                  output = [value[0], value[1], value[2]];
                }

                if (output.length) {
                  result = helpers.addUnique(result, {
                    'ruleId': parser.rule.name,
                    'line': item.start.line,
                    'column': item.start.column,
                    'message': 'Property `' + property + '` should be written more concisely as `' + output.join(' ') + '` instead of `' + value.join(' ') + '`',
                    'severity': parser.severity
                  });
                }
              }
            }
          }
        }
      });
    });
    return result;
  }
};