ENH: Read "precise-watcher" property in package.json by default

ENH: Add src/lib/read-config.js

TST: Test setting config via package.json in test/integration/src.test.js

src/index.js

@@ -1,2 +1,19 @@
-module.exports = () => {
+const readConfig = require('./lib/read-config')
+
+module.exports = (options) => {
+  const {
+    cwd,
+    config: configFilename = 'package.json',
+  } = Object(options);
+  let config = readConfig(configFilename, {cwd})
+
+  if (configFilename === 'package.json') {
+    config = Object(config)['precise-watcher']
+  }
+
+  if (!config) {
+    return false
+  }
+
+  return true
 }

src/lib/read-config.js

@@ -0,0 +1,8 @@
+const path = require('path')
+
+module.exports = (filename, {cwd}) => {
+  const userDirectory = cwd || process.cwd()
+  const filepath = path.resolve(userDirectory, filename)
+
+  return require(filepath)
+}

test/integration/src.test.js

@@ -0,0 +1,13 @@
+describe('/src', () => {
+  const preciseWatcher = require('../../src')
+
+  it('Should read config from "precise-watcher" property located in ' +
+    'users\' package.json, by default', async () => {
+    // Should return early (returning false).
+    jest.doMock('../../package.json', () => ({
+      'precise-watcher': true
+    }), { virtual: true })
+
+    expect(preciseWatcher()).toBe(true)
+  })
+})