Enable new rules in typescript-eslint and apply it to the code

gfx · gfx · commit cefdcff4b911 · 2020-01-06T12:00:29.000+09:00
diff --git a/.eslintrc.js b/.eslintrc.js
@@ -35,34 +35,37 @@ module.exports = {
     "import/no-cycle": "error",
     "import/no-default-export": "error",
 
-    "@typescript-eslint/no-unused-vars": "warn",
+    "@typescript-eslint/await-thenable": "warn",
     "@typescript-eslint/array-type": ["warn", { default: "generic" }],
     "@typescript-eslint/camelcase": "warn",
     "@typescript-eslint/class-name-casing": "warn", // to allow the initial underscore
+    "@typescript-eslint/restrict-plus-operands": ["warn", { "checkCompoundAssignments": true }],
     "@typescript-eslint/no-non-null-assertion": "warn", // NOTE: pay attention to it because it may cause unexpected behavior
+    "@typescript-eslint/no-throw-literal": "warn",
+    "@typescript-eslint/no-extra-semi": "warn",
+    "@typescript-eslint/no-extra-non-null-assertion": "warn",
+    "@typescript-eslint/no-unused-vars": "warn",
+    "@typescript-eslint/no-use-before-define": "warn",
+    "@typescript-eslint/no-for-in-array": "warn",
+    "@typescript-eslint/no-unnecessary-condition": ["warn", { "allowConstantLoopConditions": true }],
     "@typescript-eslint/prefer-for-of": "warn",
     "@typescript-eslint/prefer-includes": "warn",
     "@typescript-eslint/prefer-string-starts-ends-with": "warn",
     "@typescript-eslint/prefer-readonly": "warn",
     "@typescript-eslint/prefer-regexp-exec": "warn",
-    "@typescript-eslint/no-use-before-define": "warn",
-    "@typescript-eslint/await-thenable": "warn",
-    "@typescript-eslint/no-for-in-array": "warn",
     "@typescript-eslint/prefer-nullish-coalescing": "warn",
     "@typescript-eslint/prefer-optional-chain": "warn",
-    "@typescript-eslint/no-extra-non-null-assertion": "warn",
-    "@typescript-eslint/restrict-plus-operands": ["warn", { "checkCompoundAssignments": true } ],
 
     "@typescript-eslint/indent": "off",
-    "@typescript-eslint/no-explicit-any": "off",
     "@typescript-eslint/explicit-function-return-type": "off",
     "@typescript-eslint/explicit-member-accessibility": "off",
+    "@typescript-eslint/no-explicit-any": "off",
     "@typescript-eslint/no-object-literal-type-assertion": "off",
     "@typescript-eslint/no-empty-interface": "off",
+    "@typescript-eslint/no-empty-function": "off",
     "@typescript-eslint/no-parameter-properties": "off",
     "@typescript-eslint/no-var-requires": "off", // enforces `import x = require("x")`, which is TypeScript-specific
     "@typescript-eslint/prefer-interface": "off",
-    "@typescript-eslint/no-empty-function": "off",
 
     "prettier/prettier": "warn",
   },
diff --git a/src/Decoder.ts b/src/Decoder.ts
@@ -388,7 +388,9 @@ export class Decoder {
           state.key = object;
           state.type = State.MAP_VALUE;
           continue DECODE;
-        } else if (state.type === State.MAP_VALUE) {
+        } else {
+          // it must be `state.type === State.MAP_VALUE` here
+
           // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
           state.map[state.key!] = object;
           state.readCount++;
diff --git a/src/ExtensionCodec.ts b/src/ExtensionCodec.ts
@@ -17,12 +17,12 @@ export class ExtensionCodec implements ExtensionCodecType {
   public static readonly defaultCodec: ExtensionCodecType = new ExtensionCodec();
 
   // built-in extensions
-  private readonly builtInEncoders: Array<ExtensionEncoderType> = [];
-  private readonly builtInDecoders: Array<ExtensionDecoderType> = [];
+  private readonly builtInEncoders: Array<ExtensionEncoderType | undefined | null> = [];
+  private readonly builtInDecoders: Array<ExtensionDecoderType | undefined | null> = [];
 
   // custom extensions
-  private readonly encoders: Array<ExtensionEncoderType> = [];
-  private readonly decoders: Array<ExtensionDecoderType> = [];
+  private readonly encoders: Array<ExtensionEncoderType | undefined | null> = [];
+  private readonly decoders: Array<ExtensionDecoderType | undefined | null> = [];
 
   public constructor() {
     this.register(timestampExtension);
