Introduce basic js unit tests

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

js/jest.config.js

@@ -0,0 +1,19 @@
+module.exports = {
+  preset: "@vue/cli-plugin-unit-jest/presets/typescript-and-babel",
+  collectCoverage: true,
+  collectCoverageFrom: [
+    "**/*.{vue,ts}",
+    "!**/node_modules/**",
+    "!get_union_json.ts",
+  ],
+  coverageReporters: ["html", "text", "text-summary"],
+  // The following should fix the issue with svgs and ?inline loader (see Logo.vue), but doesn't work
+  //
+  // transform: {
+  //   "^.+\\.svg$": "<rootDir>/tests/unit/svgTransform.js",
+  // },
+  // moduleNameMapper: {
+  //   "^@/(.*svg)(\\?inline)$": "<rootDir>/src/$1",
+  //   "^@/(.*)$": "<rootDir>/src/$1",
+  // },
+};