Apply the Firefox eslint rules, minus the Firefox-specific plugins.

Fix up the myriad changes.  Justification for the large changeset for quotes: they were inconsistent before.

.eslintrc.js

@@ -0,0 +1,327 @@
+"use strict";
+
+module.exports = {
+  "env": {
+    "node": true,
+    "es6": true
+  },
+
+  "parserOptions": {
+    "ecmaVersion": 9
+  },
+
+  "globals": {
+    "fetch": false,
+    "WebAssembly": false
+  },
+
+  "rules": {
+    // Require spacing around =>
+    "arrow-spacing": "error",
+
+    // Braces only needed for multi-line arrow function blocks
+    // "arrow-body-style": ["error", "as-needed"]
+
+    // Always require spacing around a single line block
+    "block-spacing": "error",
+
+    // No newline before open brace for a block
+    "brace-style": ["error", "1tbs", { "allowSingleLine": true }],
+
+    // No space before always a space after a comma
+    "comma-spacing": ["error", {"after": true, "before": false}],
+
+    // Commas at the end of the line not the start
+    "comma-style": "error",
+
+    // Warn about cyclomatic complexity in functions.
+    // XXX Get this down to 20?
+    "complexity": ["error", 25],
+
+    // Don't require spaces around computed properties
+    "computed-property-spacing": ["error", "never"],
+
+    // Functions must always return something or nothing
+    "consistent-return": "error",
+
+    // Require braces around blocks that start a new line
+    "curly": ["error", "multi-line"],
+
+    // Encourage the use of dot notation whenever possible.
+    "dot-notation": "error",
+
+    // Always require a trailing EOL
+    "eol-last": "error",
+
+    // No spaces between function name and parentheses
+    "func-call-spacing": "error",
+
+    // Require function* name()
+    "generator-star-spacing": ["error", {"after": true, "before": false}],
+
+    // Two space indent
+    // "indent": ["error", 2, { "SwitchCase": 1 }],
+
+    // Space after colon not before in property declarations
+    "key-spacing": ["error", {
+      "afterColon": true,
+      "beforeColon": false,
+      "mode": "minimum"
+    }],
+
+    // Require spaces before and after keywords
+    "keyword-spacing": "error",
+
+    // Unix linebreaks
+    "linebreak-style": ["error", "unix"],
+
+    // Don't enforce the maximum depth that blocks can be nested. The complexity
+    // rule is a better rule to check this.
+    "max-depth": "off",
+
+    // Maximum depth callbacks can be nested.
+    "max-nested-callbacks": ["error", 10],
+
+    // Always require parenthesis for new calls
+    "new-parens": "error",
+
+    // Use [] instead of Array()
+    "no-array-constructor": "error",
+
+    // Disallow use of arguments.caller or arguments.callee.
+    "no-caller": "error",
+
+    // Disallow modifying variables of class declarations.
+    "no-class-assign": "error",
+
+    // Disallow assignment operators in conditional statements
+    "no-cond-assign": "error",
+
+    // Disallow modifying variables that are declared using const.
+    "no-const-assign": "error",
+
+    // Disallow control characters in regular expressions.
+    "no-control-regex": "error",
+
+    // Disallow the use of debugger
+    "no-debugger": "error",
+
+    // Disallow deleting variables
+    "no-delete-var": "error",
+
+    // No duplicate arguments in function declarations
+    "no-dupe-args": "error",
+
+    // Disallow duplicate class members.
+    "no-dupe-class-members": "error",
+
+    // No duplicate keys in object declarations
+    "no-dupe-keys": "error",
+
+    // No duplicate cases in switch statements
+    "no-duplicate-case": "error",
+
+    // If an if block ends with a return no need for an else block
+    "no-else-return": "error",
+
+    // No empty statements
+    "no-empty": ["error", {"allowEmptyCatch": true}],
+
+    // No empty character classes in regex
+    "no-empty-character-class": "error",
+
+    // Disallow empty destructuring
+    "no-empty-pattern": "error",
+
+    // Disallow eval and setInteral/setTimeout with strings
+    "no-eval": "error",
+
+    // No assigning to exception variable
+    "no-ex-assign": "error",
+
+    // Disallow unnecessary calls to .bind()
+    "no-extra-bind": "error",
+
+    // No using !! where casting to boolean is already happening
+    "no-extra-boolean-cast": "error",
+
+    // No double semicolon
+    "no-extra-semi": "error",
+
+    // No overwriting defined functions
+    "no-func-assign": "error",
+
+    // Disallow eval and setInteral/setTimeout with strings
+    "no-implied-eval": "error",
+
+    // No invalid regular expressions
+    "no-invalid-regexp": "error",
+
+    // No odd whitespace characters
+    "no-irregular-whitespace": "error",
+
+    // Disallow the use of the __iterator__ property
+    "no-iterator": "error",
+
+     // No labels
+    "no-labels": "error",
+
+    // Disallow unnecessary nested blocks
+    "no-lone-blocks": "error",
+
+    // No single if block inside an else block
+    "no-lonely-if": "error",
+
+    // no-tabs disallows tabs completely.
+    // "no-mixed-spaces-and-tabs": "error",
+
+    // No unnecessary spacing
+    "no-multi-spaces": ["error", { exceptions: {
+      "ArrayExpression": true,
+      "AssignmentExpression": true,
+      "ObjectExpression": true,
+      "VariableDeclarator": true
+    } }],
+
+    // No reassigning native JS objects
+    "no-native-reassign": "error",
+
+    // Nested ternary statements are confusing
+    "no-nested-ternary": "error",
+
+    // Use {} instead of new Object()
+    "no-new-object": "error",
+
+    // Dissallow use of new wrappers
+    "no-new-wrappers": "error",
+
+    // No Math() or JSON()
+    "no-obj-calls": "error",
+
+    // No octal literals
+    "no-octal": "error",
+
+    // No redeclaring variables
+    "no-redeclare": "error",
+
+    // Disallow multiple spaces in regular expressions
+    "no-regex-spaces": "error",
+
+    // Disallows unnecessary `return await ...`.
+    "no-return-await": "error",
+
+    // Disallow assignments where both sides are exactly the same
+    "no-self-assign": "error",
+
+    // No unnecessary comparisons
+    "no-self-compare": "error",
+
+    // No declaring variables from an outer scope
+    "no-shadow": "error",
+
+    // No declaring variables that hide things like arguments
+    "no-shadow-restricted-names": "error",
+
+    // Disallow sparse arrays
+    "no-sparse-arrays": "error",
+
+    // Disallow tabs.
+    "no-tabs": "error",
+
+    // No trailing whitespace
+    "no-trailing-spaces": "error",
+
+    // No using undeclared variables
+    "no-undef": "error",
+
+    // Error on newline where a semicolon is needed
+    "no-unexpected-multiline": "error",
+
+    // Disallow the use of Boolean literals in conditional expressions.
+    "no-unneeded-ternary": "error",
+
+    // No unreachable statements
+    "no-unreachable": "error",
+
+    // Disallow control flow statements in finally blocks
+    "no-unsafe-finally": "error",
+
+    // No (!foo in bar) or (!object instanceof Class)
+    "no-unsafe-negation": "error",
+
+    // No declaring variables that are never used
+    "no-unused-vars": ["error", {
+      "args": "none",
+      "vars": "local"
+    }],
+
+    // No using variables before defined
+    "no-use-before-define": ["error", "nofunc"],
+
+    // Disallow unnecessary .call() and .apply()
+    "no-useless-call": "error",
+
+    // Don't concatenate string literals together (unless they span multiple
+    // lines)
+    "no-useless-concat": "error",
+
+    // Disallow redundant return statements
+    "no-useless-return": "error",
+
+    // Disallow whitespace before properties.
+    "no-whitespace-before-property": "error",
+
+    // No using with
+    "no-with": "error",
+
+    // Require object-literal shorthand with ES6 method syntax
+    "object-shorthand": ["error", "always", { "avoidQuotes": true }],
+
+    // Require double-quotes everywhere, except where quotes are escaped
+    // or template literals are used.
+    "quotes": ["error", "double", {
+      "allowTemplateLiterals": true,
+      "avoidEscape": true
+    }],
+
+    // No spacing inside rest or spread expressions
+    "rest-spread-spacing": "error",
+
+    // Always require semicolon at end of statement
+    "semi": ["error", "always"],
+
+    // Require space before blocks
+    "space-before-blocks": "error",
+
+    // Never use spaces before function parentheses
+    "space-before-function-paren": ["error", {
+      "anonymous": "never",
+      "asyncArrow": "always",
+      "named": "never"
+    }],
+
+    // No space padding in parentheses
+    "space-in-parens": ["error", "never"],
+
+    // Require spaces around operators
+    "space-infix-ops": ["error", { "int32Hint": true }],
+
+    // ++ and -- should not need spacing
+    "space-unary-ops": ["error", {
+      "nonwords": false,
+      "overrides": {
+        "typeof": false // We tend to use typeof as a function call
+      },
+      "words": true
+    }],
+
+    // Requires or disallows a whitespace (space or tab) beginning a comment
+    "spaced-comment": "error",
+
+    // No comparisons to NaN
+    "use-isnan": "error",
+
+    // Only check typeof against valid results
+    "valid-typeof": "error"
+  }
+};