json-parse-even-better-errors - npm Package Compare versions

Comparing version 2.2.0 to 2.3.0

index.js

@@ -65,2 +65,8 @@ 'use strict'
 
+const kIndent = Symbol.for('indent')
+const kNewline = Symbol.for('newline')
+// only respect indentation if we got a line break, otherwise squash it
+// things other than objects and arrays aren't indented, so ignore those
+const formatRE = /^\s*[{\[]((?:\r?\n)+)([\s\t]*)/
+
 const parseJson = (txt, reviver, context) => {
@@ -70,3 +76,14 @@ const parseText = stripBOM(txt)
   try {
-    return JSON.parse(parseText, reviver)
+    // get the indentation so that we can save it back nicely
+    // if the file starts with {" then we have an indent of '', ie, none
+    // otherwise, pick the indentation of the next line after the first \n
+    // If the pattern doesn't match, then it means no indentation.
+    // JSON.stringify ignores symbols, so this is reasonably safe.
+    const [, newline, indent] = parseText.match(formatRE) || [, '', '']
+    const result = JSON.parse(parseText, reviver)
+    if (result && typeof result === 'object') {
+      result[kNewline] = newline
+      result[kIndent] = indent
+    }
+    return result
   } catch (e) {
@@ -73,0 +90,0 @@ if (typeof txt !== 'string' && !Buffer.isBuffer(txt)) {

package.json

 {
   "name": "json-parse-even-better-errors",
-  "version": "2.2.0",
+  "version": "2.3.0",
   "description": "JSON.parse with context information on error",
@@ -5,0 +5,0 @@ "main": "index.js",

README.md

@@ -1,6 +0,11 @@
-# json-parse-even-better-errors [![npm version](https://img.shields.io/npm/v/json-parse-even-better-errors.svg)](https://npm.im/json-parse-even-better-errors) [![license](https://img.shields.io/npm/l/json-parse-even-better-errors.svg)](https://npm.im/json-parse-even-better-errors) [![Travis](https://img.shields.io/travis/npm/json-parse-even-better-errors.svg)](https://travis-ci.org/npm/json-parse-even-better-errors) [![AppVeyor](https://ci.appveyor.com/api/projects/status/github/npm/json-parse-even-better-errors?svg=true)](https://ci.appveyor.com/project/npm/json-parse-even-better-errors) [![Coverage Status](https://coveralls.io/repos/github/npm/json-parse-even-better-errors/badge.svg?branch=latest)](https://coveralls.io/github/npm/json-parse-even-better-errors?branch=latest)
+# json-parse-even-better-errors
 
-[`json-parse-even-better-errors`](https://github.com/npm/json-parse-even-better-errors) is a Node.js library for
-getting nicer errors out of `JSON.parse()`, including context and position of the parse errors.
+[`json-parse-even-better-errors`](https://github.com/npm/json-parse-even-better-errors)
+is a Node.js library for getting nicer errors out of `JSON.parse()`,
+including context and position of the parse errors.
 
+It also preserves the newline and indentation styles of the JSON data, by
+putting them in the object or array in the `Symbol.for('indent')` and
+`Symbol.for('newline')` properties.
+
 ## Install
@@ -33,3 +38,33 @@
 * Has a `noExceptions` method that returns undefined rather than throwing.
+* Attaches the newline character(s) used to the `Symbol.for('newline')`
+  property on objects and arrays.
+* Attaches the indentation character(s) used to the `Symbol.for('indent')`
+  property on objects and arrays.
 
+## Indentation
+
+To preserve indentation when the file is saved back to disk, use
+`data[Symbol.for('indent')]` as the third argument to `JSON.stringify`, and
+if you want to preserve windows `\r\n` newlines, replace the `\n` chars in
+the string with `data[Symbol.for('newline')]`.
+
+For example:
+
+```js
+const txt = await readFile('./package.json', 'utf8')
+const data = parseJsonEvenBetterErrors(txt)
+const indent = Symbol.for('indent')
+const newline = Symbol.for('newline')
+// .. do some stuff to the data ..
+const string = JSON.stringify(data, null, data[indent]) + '\n'
+const eolFixed = data[newline] === '\n' ? string
+  : string.replace(/\n/g, data[newline])
+await writeFile('./package.json', eolFixed)
+```
+
+Indentation is determined by looking at the whitespace between the initial
+`{` and `[` and the character that follows it.  If you have lots of weird
+inconsistent indentation, then it won't track that or give you any way to
+preserve it.  Whether this is a bug or a feature is debatable ;)
+
 ### API
@@ -39,4 +74,6 @@
 
-Works just like `JSON.parse`, but will include a bit more information when an
-error happens.  This throws a `JSONParseError`.
+Works just like `JSON.parse`, but will include a bit more information when
+an error happens, and attaches a `Symbol.for('indent')` and
+`Symbol.for('newline')` on objects and arrays.  This throws a
+`JSONParseError`.
 
@@ -43,0 +80,0 @@ #### <a name="parse"></a> `parse.noExceptions(txt, reviver = null)`

No alert changes

Improved metrics

Total package byte prevSize

10119

increased by18.21%

Lines of code

99

increased by19.28%

Number of lines in readme file

97

increased by61.67%

No dependency changes