Using Istanbul With TypeScript & mocha

Thanks to @mohsen1's post the following is the minimum recommended configuration to get accurate TypeScript coverage with mocha. With this configuration, the all: true and cache: true options should work.

You will also need to npm install --save-dev source-map-support, which will also require that you have sourcemaps configured in your tsconfig.json. Inline, or not, as long as one is enabled.

#package.json

{
  "scripts": {
    "test": "nyc mocha"
  },
  "nyc": {
    "extension": [
      ".ts",
      ".tsx"
    ],
    "exclude": [
      "**/*.d.ts"
    ],
    "reporter": [
      "html"
    ],
    "all": true  
  }
}

#test/mocha.opts

--require ts-node/register
--require source-map-support/register
--recursive
<glob for your test files>