feat(crossEnv): add crossEnv which uses cross-env

Closes #1
Closes #2 (`cross-env` can do what `cross-var` does)

package.json

@@ -20,6 +20,7 @@
     "common-tags": "^1.4.0",
     "concurrently": "^3.4.0",
     "cpy-cli": "^1.0.1",
+    "cross-env": "^3.1.4",
     "is-windows": "^1.0.0",
     "mkdirp": "^0.5.1",
     "opn-cli": "^3.1.0",

src/__snapshots__/index.test.js.snap

@@ -12,6 +12,10 @@ exports[`copy as darwin 1`] = `"node node_modules/cpy-cli/cli.js \\"**/*.html\\"
 
 exports[`copy as win32 1`] = `"node node_modules/cpy-cli/cli.js \\"**/*.html\\" \\"../dist/\\" --cwd=src --parents"`;
 
+exports[`crossEnv as darwin 1`] = `"node node_modules/cross-env/bin/cross-env.js NODE_ENV=test jest"`;
+
+exports[`crossEnv as win32 1`] = `"node node_modules/cross-env/bin/cross-env.js NODE_ENV=test jest"`;
+
 exports[`ifNotWindows as darwin 1`] = `"echo main"`;
 
 exports[`ifNotWindows as win32 1`] = `"echo alternate"`;

src/index.js

@@ -23,6 +23,7 @@ export {
   copy,
   mkdirp,
   open,
+  crossEnv,
 }
 
 /**
@@ -289,6 +290,18 @@ function open(args) {
   return `${getBin('opn-cli', 'opn')} ${args}`
 }
 
+/**
+ * Gets a script that uses the cross-env binary. cross-env
+ * is a dependency of nps-utils, so you don't need to
+ * install it yourself.
+ * @param {string} args - args to pass to cross-env
+ *   learn more from http://npm.im/cross-env
+ * @return {string} - the command with the cross-env binary
+ */
+function crossEnv(args) {
+  return `${getBin('cross-env')} ${args}`
+}
+
 // utils
 
 function quoteScript(script, escaped) {

src/index.test.js

@@ -47,6 +47,7 @@ const snapshotTests = {
   mkdirp: ({mkdirp}) => mkdirp('/tmp/foo/bar/baz'),
   open: ({open}) =>
     open('http://kentcdodds.com -- "google chrome" --incognito'),
+  crossEnv: ({crossEnv}) => crossEnv('NODE_ENV=test jest'),
 }
 
 Object.keys(snapshotTests).forEach(testName => {

yarn.lock

@@ -1471,6 +1471,19 @@ create-hmac@^1.1.0, create-hmac@^1.1.2:
     create-hash "^1.1.0"
     inherits "^2.0.1"
 
+cross-env@^3.1.4:
+  version "3.1.4"
+  resolved "https://registry.yarnpkg.com/cross-env/-/cross-env-3.1.4.tgz#56e8bca96f17908a6eb1bc2012ca126f92842130"
+  dependencies:
+    cross-spawn "^3.0.1"
+
+cross-spawn@^3.0.1:
+  version "3.0.1"
+  resolved "https://registry.yarnpkg.com/cross-spawn/-/cross-spawn-3.0.1.tgz#1256037ecb9f0c5f79e3d6ef135e30770184b982"
+  dependencies:
+    lru-cache "^4.0.1"
+    which "^1.2.9"
+
 cross-spawn@^5.0.1:
   version "5.0.1"
   resolved "https://registry.yarnpkg.com/cross-spawn/-/cross-spawn-5.0.1.tgz#a3bbb302db2297cbea3c04edf36941f4613aa399"