From 9bd442da48543ab8157287d31d08a6b577ccf467 Mon Sep 17 00:00:00 2001
From: Anton Medvedev <anton@medv.io>
Date: Thu, 30 Aug 2018 22:09:12 +0700
Subject: [PATCH] Add dot feature

---
 README.md | 15 ++++++++++++---
 index.js  | 29 +++++++++++++++++++++++------
 test.js   | 18 +++++++++++-------
 3 files changed, 46 insertions(+), 16 deletions(-)

diff --git a/README.md b/README.md
index e78a5d5..4f2081c 100644
--- a/README.md
+++ b/README.md
@@ -40,7 +40,7 @@ $ echo '{"key":"value"}' | fx
 Use an anonymous function as reducer which gets JSON and processes it:
 ```
 $ echo '{"foo": [{"bar": "value"}]}' | fx 'x => x.foo[0].bar'
-"value"
+value
 ```
 
 ### This Binding
@@ -49,7 +49,16 @@ If you don't pass anonymous function `param => ...`, code will be automatically
 And you can get access to JSON by `this` keyword:
 ```
 $ echo '{"foo": [{"bar": "value"}]}' | fx 'this.foo[0].bar'
-"value"
+value
+```
+
+### Dot
+
+It is possible to omit `this` keyword:
+
+```
+$ echo '{"foo": [{"bar": "value"}]}' | fx .foo[0].bar
+value
 ```
 
 ### Chain
@@ -57,7 +66,7 @@ $ echo '{"foo": [{"bar": "value"}]}' | fx 'this.foo[0].bar'
 You can pass any number of anonymous functions for reducing JSON:
 ```
 $ echo '{"foo": [{"bar": "value"}]}' | fx 'x => x.foo' 'this[0]' 'this.bar'
-"value"
+value
 ```
 
 ### Generator
diff --git a/index.js b/index.js
index ca61078..c60d99c 100755
--- a/index.js
+++ b/index.js
@@ -10,16 +10,22 @@ const cli = meow(`
 
   Examples
     $ echo '{"key": "value"}' | fx 'x => x.key'
-    "value"
+    value
 
     $ echo '[1,2,3]' | fx 'this.map(x => x * 2)'
     [2, 4, 6]
 
     $ echo '{"items": ["one", "two"]}' | fx 'this.items' 'this[1]'
-    "two"
+    two
 
     $ echo '{"count": 0}' | fx '{...this, count: 1}'
     {"count": 1}
+    
+    $ echo '{"foo": 1, "bar": 2}' | fx ?
+    ["foo", "bar"]
+    
+    $ echo '{"key": "value"}' | fx .key
+    value
 `)
 
 async function main() {
@@ -34,6 +40,8 @@ async function main() {
 
   if (typeof result === 'undefined') {
     process.stderr.write('undefined\n')
+  } else if (typeof result === 'string') {
+    console.log(result)
   } else if (process.stdout.isTTY) {
     console.log(pretty(result))
   } else {
@@ -45,7 +53,9 @@ function reduce(json, code) {
   if (/^\w+\s*=>/.test(code)) {
     const fx = eval(code)
     return fx(json)
-  } else if (/yield/.test(code)) {
+  }
+
+  if (/yield/.test(code)) {
     const fx = eval(`
       function fn() {
         const gen = (function*(){ 
@@ -55,12 +65,19 @@ function reduce(json, code) {
       }; fn
     `)
     return fx.call(json)
-  } else if (/^\?$/.test(code)) {
+  }
+
+  if (/^\?$/.test(code)) {
     return Object.keys(json)
-  } else {
-    const fx = eval(`function fn() { return ${code} }; fn`)
+  }
+
+  if (/^\./.test(code)) {
+    const fx = eval(`function fn() { return ${code === '.' ? 'this' : 'this' + code} }; fn`)
     return fx.call(json)
   }
+
+  const fx = eval(`function fn() { return ${code} }; fn`)
+  return fx.call(json)
 }
 
 main()
diff --git a/test.js b/test.js
index 123ad3f..eadaa8a 100644
--- a/test.js
+++ b/test.js
@@ -3,26 +3,30 @@ const test = require('ava')
 const {execSync} = require('child_process')
 
 function fx(json, code = '') {
-  const output = execSync(`echo '${JSON.stringify(json)}' | node index.js ${code}`).toString('utf8')
-  return JSON.parse(output)
+  return execSync(`echo '${JSON.stringify(json)}' | node index.js ${code}`).toString('utf8')
 }
 
 test('pass', t => {
-  t.deepEqual(fx([{"greeting": "hello world"}]), [{"greeting": "hello world"}])
+  const r = fx([{"greeting": "hello world"}])
+  t.deepEqual(JSON.parse(r), [{"greeting": "hello world"}])
 })
 
 test('anon func', t => {
-  t.deepEqual(fx({"key": "value"}, "'x => x.key'"), 'value')
+  const r = fx({"key": "value"}, "'x => x.key'")
+  t.deepEqual(r, 'value\n')
 })
 
 test('this bind', t => {
-  t.deepEqual(fx([1, 2, 3, 4, 5], "'this.map(x => x * this.length)'"), [5, 10, 15, 20, 25])
+  const r = fx([1, 2, 3, 4, 5], "'this.map(x => x * this.length)'")
+  t.deepEqual(JSON.parse(r), [5, 10, 15, 20, 25])
 })
 
 test('generator', t => {
-  t.deepEqual(fx([1, 2, 3, 4, 5], "'for (let i of this) if (i % 2 == 0) yield i'"), [2, 4])
+  const r = fx([1, 2, 3, 4, 5], "'for (let i of this) if (i % 2 == 0) yield i'")
+  t.deepEqual(JSON.parse(r), [2, 4])
 })
 
 test('chain', t => {
-  t.deepEqual(fx({"items": ["foo", "bar"]}, "'this.items' 'yield* this' 'x => x[1]'"), 'bar')
+  const r = fx({"items": ["foo", "bar"]}, "'this.items' 'yield* this' 'x => x[1]'")
+  t.deepEqual(r, 'bar\n')
 })