chore: introduce prettier and run it

Adds prettier and a `format` script, and includes the results of the
initial run.

.prettierrc.json

@@ -0,0 +1,10 @@
+{
+  "bracketSpacing": false,
+  "printWidth": 80,
+  "semi": true,
+  "singleQuote": true,
+  "tabWidth": 2,
+  "trailingComma": "none",
+  "useTabs": false,
+  "arrowParens": "always"
+}

lib/chai.js

@@ -45,7 +45,7 @@ export function use(fn) {
   }
 
   return exports;
-};
+}
 
 // Utility Functions
 export {util};

lib/chai/assertion.js

@@ -49,7 +49,7 @@ import * as util from './utils/index.js';
  * @returns {unknown}
  * @private
  */
-export function Assertion (obj, msg, ssfi, lockSsfi) {
+export function Assertion(obj, msg, ssfi, lockSsfi) {
   util.flag(this, 'ssfi', ssfi || Assertion);
   util.flag(this, 'lockSsfi', lockSsfi);
   util.flag(this, 'object', obj);
@@ -60,23 +60,31 @@ export function Assertion (obj, msg, ssfi, lockSsfi) {
 }
 
 Object.defineProperty(Assertion, 'includeStack', {
-  get: function() {
-    console.warn('Assertion.includeStack is deprecated, use chai.config.includeStack instead.');
+  get: function () {
+    console.warn(
+      'Assertion.includeStack is deprecated, use chai.config.includeStack instead.'
+    );
     return config.includeStack;
   },
-  set: function(value) {
-    console.warn('Assertion.includeStack is deprecated, use chai.config.includeStack instead.');
+  set: function (value) {
+    console.warn(
+      'Assertion.includeStack is deprecated, use chai.config.includeStack instead.'
+    );
     config.includeStack = value;
   }
 });
 
 Object.defineProperty(Assertion, 'showDiff', {
-  get: function() {
-    console.warn('Assertion.showDiff is deprecated, use chai.config.showDiff instead.');
+  get: function () {
+    console.warn(
+      'Assertion.showDiff is deprecated, use chai.config.showDiff instead.'
+    );
     return config.showDiff;
   },
-  set: function(value) {
-    console.warn('Assertion.showDiff is deprecated, use chai.config.showDiff instead.');
+  set: function (value) {
+    console.warn(
+      'Assertion.showDiff is deprecated, use chai.config.showDiff instead.'
+    );
     config.showDiff = value;
   }
 });
@@ -120,7 +128,14 @@ Assertion.overwriteChainableMethod = function (name, fn, chainingBehavior) {
  * @private
  */
 
-Assertion.prototype.assert = function (expr, msg, negateMsg, expected, _actual, showDiff) {
+Assertion.prototype.assert = function (
+  expr,
+  msg,
+  negateMsg,
+  expected,
+  _actual,
+  showDiff
+) {
   var ok = util.test(this, arguments);
   if (false !== showDiff) showDiff = true;
   if (undefined === expected && undefined === _actual) showDiff = false;
@@ -130,9 +145,9 @@ Assertion.prototype.assert = function (expr, msg, negateMsg, expected, _actual,
     msg = util.getMessage(this, arguments);
     var actual = util.getActual(this, arguments);
     var assertionErrorObjectProperties = {
-        actual: actual
-      , expected: expected
-      , showDiff: showDiff
+      actual: actual,
+      expected: expected,
+      showDiff: showDiff
     };
 
     var operator = util.getOperator(this, arguments);
@@ -143,7 +158,8 @@ Assertion.prototype.assert = function (expr, msg, negateMsg, expected, _actual,
     throw new AssertionError(
       msg,
       assertionErrorObjectProperties,
-      (config.includeStack) ? this.assert : util.flag(this, 'ssfi'));
+      config.includeStack ? this.assert : util.flag(this, 'ssfi')
+    );
   }
 };
 
@@ -154,11 +170,11 @@ Assertion.prototype.assert = function (expr, msg, negateMsg, expected, _actual,
  *
  * @private
  */
-Object.defineProperty(Assertion.prototype, '_obj',
-  { get: function () {
-      return util.flag(this, 'object');
-    }
-  , set: function (val) {
-      util.flag(this, 'object', val);
-    }
+Object.defineProperty(Assertion.prototype, '_obj', {
+  get: function () {
+    return util.flag(this, 'object');
+  },
+  set: function (val) {
+    util.flag(this, 'object', val);
+  }
 });

lib/chai/config.js

@@ -1,5 +1,4 @@
 export const config = {
-
   /**
    * ### config.includeStack
    *
@@ -110,5 +109,4 @@ export const config = {
    * @public
    */
   deepEqual: null
-
 };