New precision option

Close #5

Author: MoOx

CHANGELOG.md

@@ -1,6 +1,7 @@
 # HEAD
 
 - New gnu like exceptions ([ref](https://github.com/postcss/postcss-calc/issues/4))
+- New `precision` option ([ref](https://github.com/postcss/postcss-calc/issues/5))
 # 2.1.0 - 2014-10-15
 
 - Add source of the error (gnu like message) (fix [#3](https://github.com/postcss/postcss-calc/issues/3))

README.md

@@ -9,7 +9,9 @@ This can be particularly useful with the [postcss-custom-properties](https://git
 
 ## Installation
 
-    $ npm install postcss-calc
+```console
+$ npm install postcss-calc
+```
 
 ## Usage
 
@@ -81,16 +83,31 @@ h1 {
 
 Checkout [tests](test) for more examples.
 
+### Options
+
+#### `precision` (default: `5`)
+
+Allow you to definine the precision for decimal numbers.
+
+```js
+var out = postcss()
+  .use(calc({precision: 10}))
+  .process(css)
+  .css
+```
+
 ---
 
 ## 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-calc.git
-    $ git checkout -b patch-1
-    $ npm install
-    $ npm test
+```console
+$ git clone https://github.com/postcss/postcss-calc.git
+$ git checkout -b patch-1
+$ npm install
+$ npm test
+```
 
 ## [Changelog](CHANGELOG.md)
 

index.js

@@ -7,7 +7,9 @@ var helpers = require("postcss-message-helpers")
 /**
  * PostCSS plugin to reduce calc() function calls.
  */
-module.exports = function plugin() {
+module.exports = function plugin(options) {
+  options = options || {}
+
   return function(style) {
     style.eachDecl(function transformDecl(decl) {
       if (!decl.value) {
@@ -19,7 +21,7 @@ module.exports = function plugin() {
           return decl.value
         }
 
-        return reduceCSSCalc(decl.value)
+        return reduceCSSCalc(decl.value, options.precision)
       })
     })
   }

package.json

@@ -21,8 +21,8 @@
     "index.js"
   ],
   "dependencies": {
-    "reduce-css-calc": "^1.1.2"
     "postcss-message-helpers": "^1.1.0",
+    "reduce-css-calc": "^1.2.0"
   },
   "devDependencies": {
     "jscs": "^1.6.2",

test/fixtures/calc.actual.css

@@ -0,0 +1,8 @@
+stuff {
+  dont: care;
+  ignore: calc(new(blah));
+  resolved: 0.125rem otherfn(blah);
+  unresolved: calc(1.125rem - 1px);
+  prefixed-unresolved: -webkit-calc(1.125rem - 1px);
+  z-index: 111;
+}

test/calc.css renamed to test/fixtures/calc.css

@@ -0,0 +1,3 @@
+calc {
+  value: 0.333;
+}

test/calc.out.css renamed to test/fixtures/calc.expected.css

@@ -0,0 +1,3 @@
+calc {
+  value: calc(1/3);
+}

test/fixtures/precision.actual.css

@@ -0,0 +1,3 @@
+calc {
+  value: 0.333;
+}

test/fixtures/precision.css

@@ -1,24 +1,35 @@
-var test = require("tape")
-
-var calc = require("..")
+var fs = require("fs")
 
-var read = require("fs").readFileSync
+var test = require("tape")
 var postcss = require("postcss")
 var customProperties = require("postcss-custom-properties")
+var calc = require("..")
+
+function fixturePath(name) {
+  return "test/fixtures/" + name + ".css"
+}
 
 function fixture(name) {
-  return read("test/" + name + ".css", "utf8").trim()
+  return fs.readFileSync(fixturePath(name), "utf8").trim()
 }
 
-test("resolve what is possible in complex calc", function(t) {
+function compareFixtures(t, name, options, message) {
   var actual = postcss()
     .use(customProperties())
-    .use(calc())
-    .process(fixture("calc"))
-    .css
-    .trim()
-  var expected = fixture("calc.out")
-  t.equal(actual, expected)
+    .use(calc(options))
+    .process(fixture(name), {from: fixturePath(name)})
+    .css.trim()
+
+  // handy thing: checkout actual in the *.actual.css file
+  fs.writeFile(fixturePath(name + ".actual"), actual)
+
+  return t.equal(actual, fixture(name + ".expected"), message ? message : "processed fixture '" + name + "' should be equal to expected output")
+}
+
+test("calc", function(t) {
+  compareFixtures(t, "calc", {}, "should resolve what is possible in complex calc")
+
+  compareFixtures(t, "precision", {precision: 3}, "should have a precision option that allow to control decimal precision of calcuations")
 
   t.end()
 })