feat: Allow setting the line count as diff context

Author: prantlf

README.md

@@ -136,6 +136,7 @@ Usage: `jsonlint [options] [<file, directory, pattern> ...]`
     -V, --validate [file]        JSON schema file to use for validation
     -e, --environment [env]      which specification of JSON Schema the
                                   validation file uses
+    -x, --context [num]          line count used as the diff context (default: 3)
     -l, --log-files              print only the parsed file names to stdout
     -q, --quiet                  do not print the parsed json to stdout
     -n, --continue               continue with other files if an error occurs

lib/cli.js

@@ -32,6 +32,7 @@ const commander = require('commander')
   .option('-D, --no-duplicate-keys', 'report duplicate object keys as an error')
   .option('-V, --validate [file]', 'JSON schema file to use for validation')
   .option('-e, --environment [env]', 'which specification of JSON Schema the validation file uses')
+  .option('-x, --context [num]', 'line count used as the diff context', 3)
   .option('-l, --log-files', 'print only the parsed file names to stdout')
   .option('-q, --quiet', 'do not print the parsed json to stdout')
   .option('-n, --continue', 'continue with other files if an error occurs')
@@ -218,7 +219,7 @@ function ensureLineBreak (parsed, source) {
 
 function checkContents (file, source, parsed) {
   const { createTwoFilesPatch, structuredPatch } = require('diff')
-  const structured = structuredPatch(`${file}.orig`, file, source, parsed, '', '', { context: 3 })
+  const structured = structuredPatch(`${file}.orig`, file, source, parsed, '', '', { context: options.context })
   const length = structured.hunks && structured.hunks.length
   if (length > 0) {
     const hunk = length === 1 ? 'hunk differs' : 'hunks differ'
@@ -231,7 +232,7 @@ function checkContents (file, source, parsed) {
       console.error(message)
     }
     if (!options.quiet) {
-      const diff = createTwoFilesPatch(`${file}.orig`, file, source, parsed, '', '', { context: 3 })
+      const diff = createTwoFilesPatch(`${file}.orig`, file, source, parsed, '', '', { context: options.context })
       console.log(diff)
     }
     if (options.continue) {
@@ -253,10 +254,10 @@ function diffContents(file, source, parsed) {
   const compact = options.quiet || options.compact
   let diff, length
   if (compact) {
-    diff = structuredPatch(`${file}.orig`, file, source, parsed, '', '', { context: 3 })
+    diff = structuredPatch(`${file}.orig`, file, source, parsed, '', '', { context: options.context })
     length = diff.hunks && diff.hunks.length
   } else {
-    diff = createTwoFilesPatch(`${file}.orig`, file, source, parsed, '', '', { context: 3 })
+    diff = createTwoFilesPatch(`${file}.orig`, file, source, parsed, '', '', { context: options.context })
     length = diff.split(/\r?\n/).length - 4
   }
   if (length > 0) {