modernize codebase: es6 upgrade

.c8rc.json

@@ -0,0 +1,11 @@
+{
+  "include": ["lib/**/*.js"],
+  "exclude": ["/test/**/*.spec.js"],
+  "extension": [".js"],
+  "check-coverage": true,
+  "lines": 85,
+  "statements": 85,
+  "functions": 85,
+  "branches": 85,
+  "reporter": ["lcov", "text", "text-summary", "html"]
+}

.gitignore

@@ -1,6 +1,6 @@
 node_modules
 !bin/*.js
 /lib-cov
-test/*.js
 coverage.html
-.idea
+.idea
+coverage

.prettierignore

@@ -0,0 +1,4 @@
+node_modules/
+package-lock.json
+doc/
+old-coffee-*/

.prettierrc.json

@@ -0,0 +1,8 @@
+{
+  "semi": true,
+  "singleQuote": true,
+  "useTabs": false,
+  "tabWidth": 2,
+  "trailingComma": "es5",
+  "printWidth": 9999
+}

bin/json-diff.js

@@ -1,2 +1,5 @@
 #!/usr/bin/env node
-require('../lib/cli')(process.argv.slice(2));
+
+import { CLI } from '../lib/cli.js';
+
+CLI(process.argv.slice(2));

eslint.config.js

@@ -0,0 +1,22 @@
+import js from '@eslint/js';
+import prettier from 'eslint-plugin-prettier/recommended';
+import globals from 'globals';
+
+export default [
+  js.configs.recommended,
+  prettier, // Enforces Prettier formatting rules via ESLint
+  {
+    languageOptions: {
+      ecmaVersion: 'latest',
+      sourceType: 'module',
+      globals: {
+        ...globals.node,
+        ...globals.mocha, // Recognizes mocha primitives like 'describe' and 'it'
+      },
+    },
+    rules: {
+      'no-unused-vars': ['warn', { argsIgnorePattern: '^_' }],
+      'no-console': 'warn',
+    },
+  },
+];

lib/cli.js

@@ -1,11 +1,12 @@
-const fs = require('fs')
-const tty = require('tty')
+import fs from 'fs';
+import tty from 'tty';
 
-const { diff } = require('./index')
-const { colorize } = require('./colorize')
+import { diff } from './index';
+import { colorize } from './colorize';
 
-module.exports = function (argv) {
+export const CLI = function (argv) {
   const options = require('dreamopt')(
+    /* prettier-ignore */
     [
       'Usage: json-diff [-vCjfoxnskKp] first.json second.json',
       '  <first.json>              Old file #var(file1) #required',
@@ -25,62 +26,62 @@ module.exports = function (argv) {
       '  -p, --precision DECIMALS  Round all floating point numbers to this number of decimal places prior to comparison'
     ],
     argv
-  )
+  );
 
-  options.outputKeys = options.outputKeys ? options.outputKeys.split(',') : []
-  options.excludeKeys = options.excludeKeys ? options.excludeKeys.split(',') : []
+  options.outputKeys = options.outputKeys ? options.outputKeys.split(',') : [];
+  options.excludeKeys = options.excludeKeys ? options.excludeKeys.split(',') : [];
 
   if (options.verbose) {
-    process.stderr.write(`${JSON.stringify(options, null, 2)}\n`)
+    process.stderr.write(`${JSON.stringify(options, null, 2)}\n`);
   }
 
   if (options.verbose) {
-    process.stderr.write('Loading files...\n')
+    process.stderr.write('Loading files...\n');
   }
-  const data1 = fs.readFileSync(options.file1, 'utf8')
-  const data2 = fs.readFileSync(options.file2, 'utf8')
+  const data1 = fs.readFileSync(options.file1, 'utf8');
+  const data2 = fs.readFileSync(options.file2, 'utf8');
 
   if (options.verbose) {
-    process.stderr.write('Parsing old file...\n')
+    process.stderr.write('Parsing old file...\n');
   }
-  const json1 = JSON.parse(data1)
+  const json1 = JSON.parse(data1);
 
   if (options.verbose) {
-    process.stderr.write('Parsing new file...\n')
+    process.stderr.write('Parsing new file...\n');
   }
-  const json2 = JSON.parse(data2)
+  const json2 = JSON.parse(data2);
 
   if (options.verbose) {
-    process.stderr.write('Running diff...\n')
+    process.stderr.write('Running diff...\n');
   }
 
-  const result = diff(json1, json2, options)
+  const result = diff(json1, json2, options);
 
   if (options.color == null) {
-    options.color = tty.isatty(process.stdout.fd)
+    options.color = tty.isatty(process.stdout.fd);
   }
 
   if (result) {
     if (options.raw) {
       if (options.verbose) {
-        process.stderr.write('Serializing JSON output...\n')
+        process.stderr.write('Serializing JSON output...\n');
       }
-      process.stdout.write(JSON.stringify(result, null, 2) + '\n')
+      process.stdout.write(JSON.stringify(result, null, 2) + '\n');
     } else {
       if (options.verbose) {
-        process.stderr.write('Producing colored output...\n')
+        process.stderr.write('Producing colored output...\n');
       }
       const colorizeOptions = {
         color: options.color,
-        maxElisions: options.maxElisions
-      }
-      process.stdout.write(colorize(result, colorizeOptions))
+        maxElisions: options.maxElisions,
+      };
+      process.stdout.write(colorize(result, colorizeOptions));
     }
-    process.exit(1)
+    process.exit(1);
   } else {
     if (options.verbose) {
-      process.stderr.write('No diff')
+      process.stderr.write('No diff');
     }
-    process.exit(0)
+    process.exit(0);
   }
-}
+};

lib/colorize.js

@@ -1,117 +1,116 @@
-const color = require('colors/safe')
-
-const { extendedTypeOf } = require('./util')
+import color from 'colors/safe.js';
+import { extendedTypeOf } from './util.js';
 
 const Theme = {
-  ' ' (s) { return s },
+  ' ': function (s) {
+    return s;
+  },
   '+': color.green,
-  '-': color.red
-}
+  '-': color.red,
+};
 
 const subcolorizeToCallback = function (options, key, diff, output, color, indent) {
-  let subvalue
-  const prefix = key ? `${key}: ` : ''
-  const subindent = indent + '  '
+  let subvalue;
+  const prefix = key ? `${key}: ` : '';
+  const subindent = indent + '  ';
 
   const outputElisions = (n) => {
-    const maxElisions = options.maxElisions === undefined ? Infinity : options.maxElisions
+    const maxElisions = options.maxElisions === undefined ? Infinity : options.maxElisions;
     if (n < maxElisions) {
       for (let i = 0; i < n; i++) {
-        output(' ', subindent + '...')
+        output(' ', subindent + '...');
       }
     } else {
-      output(' ', subindent + `... (${n} entries)`)
+      output(' ', subindent + `... (${n} entries)`);
     }
-  }
+  };
 
   switch (extendedTypeOf(diff)) {
     case 'object':
-      if (('__old' in diff) && ('__new' in diff) && (Object.keys(diff).length === 2)) {
-        subcolorizeToCallback(options, key, diff.__old, output, '-', indent)
-        return subcolorizeToCallback(options, key, diff.__new, output, '+', indent)
+      if ('__old' in diff && '__new' in diff && Object.keys(diff).length === 2) {
+        subcolorizeToCallback(options, key, diff.__old, output, '-', indent);
+        return subcolorizeToCallback(options, key, diff.__new, output, '+', indent);
       } else {
-        output(color, `${indent}${prefix}{`)
+        output(color, `${indent}${prefix}{`);
         for (const subkey of Object.keys(diff)) {
-          let m
-          subvalue = diff[subkey]
+          let m;
+          subvalue = diff[subkey];
           if ((m = subkey.match(/^(.*)__deleted$/))) {
-            subcolorizeToCallback(options, m[1], subvalue, output, '-', subindent)
+            subcolorizeToCallback(options, m[1], subvalue, output, '-', subindent);
           } else if ((m = subkey.match(/^(.*)__added$/))) {
-            subcolorizeToCallback(options, m[1], subvalue, output, '+', subindent)
+            subcolorizeToCallback(options, m[1], subvalue, output, '+', subindent);
           } else {
-            subcolorizeToCallback(options, subkey, subvalue, output, color, subindent)
+            subcolorizeToCallback(options, subkey, subvalue, output, color, subindent);
           }
         }
-        return output(color, `${indent}}`)
+        return output(color, `${indent}}`);
       }
 
     case 'array': {
-      output(color, `${indent}${prefix}[`)
+      output(color, `${indent}${prefix}[`);
 
-      let looksLikeDiff = true
+      let looksLikeDiff = true;
       for (const item of diff) {
-        if ((extendedTypeOf(item) !== 'array') || !((item.length === 2) || ((item.length === 1) && (item[0] === ' '))) || !(typeof (item[0]) === 'string') || (item[0].length !== 1) || !([' ', '-', '+', '~'].includes(item[0]))) {
-          looksLikeDiff = false
+        if (extendedTypeOf(item) !== 'array' || !(item.length === 2 || (item.length === 1 && item[0] === ' ')) || !(typeof item[0] === 'string') || item[0].length !== 1 || ![' ', '-', '+', '~'].includes(item[0])) {
+          looksLikeDiff = false;
         }
       }
 
       if (looksLikeDiff) {
-        let op
-        let elisionCount = 0
+        let op;
+        let elisionCount = 0;
         for ([op, subvalue] of diff) {
           if (op === ' ' && subvalue == null) {
-            elisionCount++
+            elisionCount++;
           } else {
             if (elisionCount > 0) {
-              outputElisions(elisionCount)
+              outputElisions(elisionCount);
             }
-            elisionCount = 0
+            elisionCount = 0;
 
             if (![' ', '~', '+', '-'].includes(op)) {
-              throw new Error(`Unexpected op '${op}' in ${JSON.stringify(diff, null, 2)}`)
+              throw new Error(`Unexpected op '${op}' in ${JSON.stringify(diff, null, 2)}`);
             }
-            if (op === '~') { op = ' ' }
-            subcolorizeToCallback(options, '', subvalue, output, op, subindent)
+            if (op === '~') op = ' ';
+
+            subcolorizeToCallback(options, '', subvalue, output, op, subindent);
           }
         }
         if (elisionCount > 0) {
-          outputElisions(elisionCount)
+          outputElisions(elisionCount);
         }
       } else {
         for (subvalue of diff) {
-          subcolorizeToCallback(options, '', subvalue, output, color, subindent)
+          subcolorizeToCallback(options, '', subvalue, output, color, subindent);
         }
       }
 
-      return output(color, `${indent}]`)
+      return output(color, `${indent}]`);
     }
 
     default:
       if (diff === 0 || diff === null || diff === false || diff === '' || diff) {
-        return output(color, indent + prefix + JSON.stringify(diff))
+        return output(color, indent + prefix + JSON.stringify(diff));
       }
   }
-}
+};
 
-const colorizeToCallback = (diff, options, output) =>
-  subcolorizeToCallback(options, '', diff, output, ' ', '')
+export const colorizeToCallback = (diff, options, output) => subcolorizeToCallback(options, '', diff, output, ' ', '');
 
-const colorizeToArray = function (diff, options = {}) {
-  const output = []
-  colorizeToCallback(diff, options, (color, line) => output.push(`${color}${line}`))
-  return output
-}
+export const colorizeToArray = function (diff, options = {}) {
+  const output = [];
+  colorizeToCallback(diff, options, (color, line) => output.push(`${color}${line}`));
+  return output;
+};
 
-const colorize = function (diff, options = {}) {
-  const output = []
+export const colorize = function (diff, options = {}) {
+  const output = [];
   colorizeToCallback(diff, options, function (color, line) {
     if (options.color != null ? options.color : true) {
-      return output.push(((options.theme != null ? options.theme[color] : undefined) != null ? (options.theme != null ? options.theme[color] : undefined) : Theme[color])(`${color}${line}`) + '\n')
+      return output.push(((options.theme != null ? options.theme[color] : undefined) != null ? (options.theme != null ? options.theme[color] : undefined) : Theme[color])(`${color}${line}`) + '\n');
     } else {
-      return output.push(`${color}${line}\n`)
+      return output.push(`${color}${line}\n`);
     }
-  })
-  return output.join('')
-}
-
-module.exports = { colorize, colorizeToArray, colorizeToCallback }
+  });
+  return output.join('');
+};