type guard helper functions

src/constants.ts

@@ -6,6 +6,14 @@ export const SUB_INCLUDE_CONFIG = "include";
 export const INCLUDE_CONFIG = `${packageJson.name}.${SUB_INCLUDE_CONFIG}`;
 export const VERSION_STATE = "version";
 
+export type Languages = {
+  [key: string]: {
+    name: string;
+    scopeName: string;
+    stripIndent: boolean;
+  };
+};
+
 /* eslint sort-keys: ["error", "asc"] */
 export const LANGUAGES = {
   bat: "source.batchfile",
@@ -146,12 +154,3 @@ export const LANGUAGES = {
   xsl: "text.xml.xsl",
   yaml: "source.yaml",
 };
-/* eslint-disable sort-keys */
-
-export type Languages = {
-  [key: string]: {
-    name: string;
-    scopeName: string;
-    stripIndent: boolean;
-  };
-};

src/generate.ts

@@ -1,42 +1,35 @@
 import { LANGUAGES, Languages } from "./constants";
 import { InjectionGrammar } from "./injection-grammar";
 import { Package } from "./package";
+import { hasBoolKey, hasStringKey } from "./utils";
 
-const normalizeLanguages = (languages: { [key: string]: unknown }) => {
-  const normalizedLanguages: Languages = {};
+const parseLanguages = (languages: { [key: string]: unknown }): Languages => {
+  const parsedLanguages: Languages = {};
   for (const id in languages) {
     let language = languages[id];
     if (typeof language === "string") {
       language = { scopeName: language };
     }
 
     if (typeof language === "object" && language !== null) {
-      if (!("scopeName" in language)) {
+      if (!hasStringKey(language, "scopeName")) {
         continue;
       }
 
-      if (typeof language.scopeName !== "string") {
-        continue;
-      }
-
-      normalizedLanguages[id] = {
-        name:
-          "name" in language && typeof language.name === "string"
-            ? language.name
-            : id,
+      parsedLanguages[id] = {
+        name: hasStringKey(language, "name") ? language.name : id,
         scopeName: language.scopeName,
-        stripIndent:
-          "stripIndent" in language && typeof language.stripIndent === "boolean"
-            ? language.stripIndent
-            : false,
+        stripIndent: hasBoolKey(language, "stripIndent")
+          ? language.stripIndent
+          : false,
       };
     }
   }
-  return normalizedLanguages;
+  return parsedLanguages;
 };
 
 export const generateFiles = (languages = LANGUAGES) => {
-  const parsedLanguages = normalizeLanguages(languages);
+  const parsedLanguages = parseLanguages(languages);
   const grammars = [
     new InjectionGrammar("source.yaml", parsedLanguages),
     new InjectionGrammar("source.github-actions-workflow", parsedLanguages),

src/utils.ts

@@ -0,0 +1,20 @@
+export function hasKey<K extends string>(
+  obj: object,
+  key: K,
+): obj is { [P in K]: unknown } {
+  return key in obj;
+}
+
+export function hasStringKey<K extends string>(
+  obj: object,
+  key: K,
+): obj is { [P in K]: string } {
+  return hasKey(obj, key) && typeof obj[key] === "string";
+}
+
+export function hasBoolKey<K extends string>(
+  obj: object,
+  key: K,
+): obj is { [P in K]: boolean } {
+  return hasKey(obj, key) && typeof obj[key] === "boolean";
+}