Rewrite

Author: andyjansson

.babelrc

@@ -0,0 +1,12 @@
+{
+  "presets": ["es2015-loose", "stage-0"],
+  "plugins": ["add-module-exports"],
+  "env": {
+    "development": {
+      "sourceMaps": "inline"
+    },
+    "test": {
+      "plugins": ["istanbul"]
+    }
+  }
+}

.eslintrc

@@ -0,0 +1,86 @@
+---
+parser: babel-eslint
+plugins:
+  - babel
+  - import
+
+root: true
+extends: eslint:recommended
+
+#ecmaFeatures:
+#  modules: true
+
+env:
+  es6: true
+  browser: true
+  node: true
+
+rules:
+#  babel/object-curly-spacing: [2]
+#  brace-style: [2, 1tbs, {allowSingleLine: false}]
+  camelcase: [2]
+#  comma-dangle: [2, always-multiline]
+  comma-spacing: [2]
+  curly: [error, multi-or-nest]
+  dot-notation: [2]
+  eol-last: [2]
+  eqeqeq: [2]
+  handle-callback-err: [2]
+  import/export: [2]
+  import/imports-first: [2]
+  import/named: [2]
+  import/namespace: [2, {allowComputed: true}]
+  import/newline-after-import: [2]
+  import/no-duplicates: [2]
+  import/no-mutable-exports: [2]
+  import/no-named-as-default: [2]
+  import/no-named-as-default-member: [2]
+#  import/no-unresolved: [2, {"commonjs": true}]
+  import/order: [2]
+  import/prefer-default-export: [2]
+  indent: [2, 2, { "SwitchCase": 1 }]
+  keyword-spacing: [2]
+  new-cap: [2]
+  new-parens: [2]
+  no-alert: [2]
+  no-caller: [2]
+  no-case-declarations: [0]
+  no-const-assign: [2]
+  no-constant-condition: [2]
+  no-dupe-args: [2]
+  no-dupe-keys: [2]
+  no-empty: [2]
+  no-empty-character-class: [2]
+  no-eval: [2]
+  no-irregular-whitespace: [2]
+  no-labels: [2]
+  no-lonely-if: [2]
+  no-multiple-empty-lines: [2]
+  no-new: [2]
+  no-octal: [2]
+  no-proto: [2]
+  no-redeclare: [2]
+  no-return-assign: [2]
+  no-self-assign: [2]
+  no-self-compare: [2]
+  no-shadow: [2]
+  no-shadow-restricted-names: [2]
+  no-sparse-arrays: [2]
+  no-undef: [2]
+  no-unreachable: [2]
+  no-unused-vars: [2]
+  no-useless-call: [2]
+  no-var: [2]
+  no-void: [2]
+  no-warning-comments: [2]
+  no-with: [2]
+  quote-props: [2, as-needed]
+  prefer-arrow-callback: [2]
+  radix: [2]
+  semi: [2, always]
+  semi-spacing: [2]
+#  space-before-function-paren: [2, always]
+  space-before-blocks: [2, always]
+  spaced-comment: [2, always]
+  strict: [2, global]
+  yoda: [2, never]

.jscsrc

@@ -0,0 +1,83 @@
+'use strict';
+
+var _ava = require('ava');
+
+var _ava2 = _interopRequireDefault(_ava);
+
+var _ = require('..');
+
+var _2 = _interopRequireDefault(_);
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+function testFixture(t, fixture) {
+  var expected = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : null;
+  var precision = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : 5;
+
+  if (expected === null) expected = fixture;
+
+  var out = (0, _2.default)(fixture, precision);
+  t.deepEqual(out, expected);
+}
+
+function testThrows(t, fixture, expected) {
+  var precision = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : 5;
+
+  t.throws(function () {
+    return (0, _2.default)(fixture, precision);
+  }, expected);
+}
+
+(0, _ava2.default)('should reduce simple calc (1)', testFixture, 'calc(1px + 1px)', '2px');
+
+(0, _ava2.default)('should reduce simple calc (2)', testFixture, 'calc(3em - 1em)', '2em');
+
+(0, _ava2.default)('should reduce simple calc (3)', testFixture, 'calc(1rem * 1.5)', '1.5rem');
+
+(0, _ava2.default)('should reduce simple calc (4)', testFixture, 'calc(2ex / 2)', '1ex');
+
+(0, _ava2.default)('should ignore value surrounding calc function (1)', testFixture, 'a calc(1px + 1px)', 'a 2px');
+
+(0, _ava2.default)('should ignore value surrounding calc function (2)', testFixture, 'calc(1px + 1px) a', '2px a');
+
+(0, _ava2.default)('should ignore value surrounding calc function (3)', testFixture, 'a calc(1px + 1px) b', 'a 2px b');
+
+(0, _ava2.default)('should ignore value surrounding calc function (4)', testFixture, 'a calc(1px + 1px) b calc(1em + 2em) c', 'a 2px b 3em c');
+
+(0, _ava2.default)('should reduce calc with newline characters', testFixture, 'calc(\n1rem \n* 2 \n* 1.5)', '3rem');
+
+(0, _ava2.default)('should preserve calc with incompatible units', testFixture, 'calc(100% + 1px)', 'calc(100% + 1px)');
+
+(0, _ava2.default)('should parse fractions without leading zero', testFixture, 'calc(2rem - .14285em)', 'calc(2rem - 0.14285em)');
+
+(0, _ava2.default)('should handle precision correctly (1)', testFixture, 'calc(1/100)', '0.01');
+
+(0, _ava2.default)('should handle precision correctly (2)', testFixture, 'calc(5/1000000)', '0.00001');
+
+(0, _ava2.default)('should handle precision correctly (3)', testFixture, 'calc(5/1000000)', '0.000005', 6);
+
+(0, _ava2.default)('should reduce browser-prefixed calc (1)', testFixture, '-webkit-calc(1px + 1px)', '2px');
+
+(0, _ava2.default)('should reduce browser-prefixed calc (2)', testFixture, '-moz-calc(1px + 1px)', '2px');
+
+(0, _ava2.default)('should discard zero values (#2) (1)', testFixture, 'calc(100vw / 2 - 6px + 0px)', 'calc(50vw - 6px)');
+
+(0, _ava2.default)('should discard zero values (#2) (2)', testFixture, 'calc(500px - 0px)', '500px');
+
+(0, _ava2.default)('should not perform addition on unitless values (#3)', testFixture, 'calc(1px + 1)', 'calc(1px + 1)');
+
+(0, _ava2.default)('should produce simpler result (postcss-calc#25) (1)', testFixture, 'calc(14px + 6 * ((100vw - 320px) / 448))', 'calc(9.71px + 1.34vw)', 2);
+
+(0, _ava2.default)('should produce simpler result (postcss-calc#25) (2)', testFixture, '-webkit-calc(14px + 6 * ((100vw - 320px) / 448))', '-webkit-calc(9.71px + 1.34vw)', 2);
+
+(0, _ava2.default)('should reduce mixed units of time (postcss-calc#33)', testFixture, 'calc(1s - 50ms)', '0.95s');
+
+(0, _ava2.default)('should correctly reduce calc with mixed units (cssnano#211)', testFixture, 'bar:calc(99.99% * 1/1 - 0rem)', 'bar:99.99%');
+
+(0, _ava2.default)('should apply algebraic reduction (cssnano#319)', testFixture, 'bar:calc((100px - 1em) + (-50px + 1em))', 'bar:50px');
+
+(0, _ava2.default)('should apply optimization (cssnano#320)', testFixture, 'bar:calc(50% + (5em + 5%))', 'bar:calc(55% + 5em)');
+
+(0, _ava2.default)('should throw an exception when attempting to divide by zero', testThrows, 'calc(500px/0)', /Cannot divide by zero/);
+
+(0, _ava2.default)('should throw an exception when attempting to divide by unit', testThrows, 'calc(500px/2px)', 'Cannot divide by "px", number expected');

.jshintrc

@@ -0,0 +1,44 @@
+'use strict';
+
+exports.__esModule = true;
+
+var _postcssValueParser = require('postcss-value-parser');
+
+var _postcssValueParser2 = _interopRequireDefault(_postcssValueParser);
+
+var _parser = require('./parser');
+
+var _reducer = require('./lib/reducer');
+
+var _reducer2 = _interopRequireDefault(_reducer);
+
+var _stringifier = require('./lib/stringifier');
+
+var _stringifier2 = _interopRequireDefault(_stringifier);
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+var MATCH_CALC = /((?:\-[a-z]+\-)?calc)/;
+
+exports.default = function (value) {
+    var precision = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : 5;
+
+    return (0, _postcssValueParser2.default)(value).walk(function (node) {
+        // skip anything which isn't a calc() function
+        if (node.type !== 'function' || !MATCH_CALC.test(node.value)) return;
+
+        // stringify calc expression and produce an AST
+        var contents = _postcssValueParser2.default.stringify(node.nodes);
+        var ast = _parser.parser.parse(contents);
+
+        // reduce AST to its simplest form, that is, either to a single value
+        // or a simplified calc expression
+        var reducedAst = (0, _reducer2.default)(ast, precision);
+
+        // stringify AST and write it back
+        node.type = 'word';
+        node.value = (0, _stringifier2.default)(node.value, reducedAst, precision);
+    }, true).toString();
+};
+
+module.exports = exports['default'];