disable showing based on npm loglevel (#14)

- Do not show if npm's loglevel is set to warn, error or silent
- Update Readme with instructions
- Add Jest testing

README.md

@@ -25,5 +25,7 @@ And in your `package.json` add:
 ## Disabling this message
 In some places (e.g. CI) you may want to disable this output. You can do this by setting the environment variable `DISABLE_OPENCOLLECTIVE=true`.
 
+It will not be shown if npm's log level is set to silent (`--silent`), warn (`--quiet`), or error (`--loglevel error`).
+
 Note: This is a lightweight alternative to the [opencollective-cli](https://github.com/opencollective/opencollective-cli) that offers a more complete postinstall message with the current balance and ASCII logo of the collective.
 

index.js

@@ -1,11 +1,13 @@
 #!/usr/bin/env node
-if (process.env.DISABLE_OPENCOLLECTIVE && process.env.DISABLE_OPENCOLLECTIVE !== '0' && process.env.DISABLE_OPENCOLLECTIVE.toLowerCase() !== 'false') {
-  return;
-}
-var pkg = require(require('path').resolve('./package.json'));
-if (pkg.collective) {
-  console.log(`\u001b[96m\u001b[1mThank you for using ${pkg.name}!\u001b[96m\u001b[1m`);
-  console.log(`\u001b[0m\u001b[96mIf you rely on this package, please consider supporting our open collective:\u001b[22m\u001b[39m`);
-  console.log(`> \u001b[94m${pkg.collective.url}/donate\u001b[0m\n`);
-}
+var envDisable = Boolean(process.env.DISABLE_OPENCOLLECTIVE);
+var logLevel = process.env.npm_config_loglevel;
+var logLevelDisplay = ['silent', 'error', 'warn'].indexOf(logLevel) > -1;
 
+if (!envDisable && !logLevelDisplay) {
+  var pkg = require(require('path').resolve('./package.json'));
+  if (pkg.collective) {
+    console.log(`\u001b[96m\u001b[1mThank you for using ${pkg.name}!\u001b[96m\u001b[1m`);
+    console.log(`\u001b[0m\u001b[96mIf you rely on this package, please consider supporting our open collective:\u001b[22m\u001b[39m`);
+    console.log(`> \u001b[94m${pkg.collective.url}/donate\u001b[0m\n`);
+  }
+}

index.test.js

@@ -0,0 +1,69 @@
+jest.mock('./package.json', () => ({
+  name: 'testpkg2',
+  collective: {url: 'testurl'}
+}), {virtual: true});
+
+describe('test all the things', () => {
+  const env = global.process.env;
+  const console = global.console;
+  beforeEach(() => {
+    global.console = {log: jest.fn(), warn: global.console.warn};
+  });
+  afterEach(() => {
+    global.process.env = env;
+    global.console.log.mockReset();
+    global.console = console;
+    jest.resetModules();
+  });
+
+  describe('outputs the correct values', () => {
+    it('when called without args', () =>{
+      expect(global.console.log).not.toHaveBeenCalled();
+      require('./index');
+      expect(global.console.log).toHaveBeenCalledTimes(3);
+      expect(global.console.log).toHaveBeenNthCalledWith(1,
+        `\u001b[96m\u001b[1mThank you for using testpkg2!\u001b[96m\u001b[1m`
+      );
+      expect(global.console.log).toHaveBeenNthCalledWith(3,
+        `> \u001b[94mtesturl/donate\u001b[0m\n`
+      );
+    });
+
+    [0, false].forEach(falsy => {
+      it(`when Disable is set to ${falsy}`, () => {
+        global.process.env = {DISABLE_OPENCOLLECTIVE: falsy};
+        expect(global.console.log).not.toHaveBeenCalled();
+        require('./index');
+        expect(global.console.log).toHaveBeenCalledTimes(3);
+      });
+    });
+
+    ['notice', 'http', 'timing', 'info', 'verbose', 'silly'].forEach(log => {
+      it(`when config_loglevel is set to ${log}`, () => {
+        global.process.env = {npm_config_loglevel: log}
+        expect(global.console.log).not.toHaveBeenCalled();
+        require('./index');
+        expect(global.console.log).toHaveBeenCalledTimes(3);
+      });
+    });
+  });
+
+  describe('does not show output', () => {
+    [1, true].forEach(truthy => {
+      it(`when Disable is set to ${truthy}`, () => {
+        global.process.env = {DISABLE_OPENCOLLECTIVE: truthy};
+        expect(global.console.log).not.toHaveBeenCalled();
+        require('./index');
+        expect(global.console.log).not.toHaveBeenCalled();
+      });
+    });
+
+    ['warn', 'error', 'silent'].forEach(log => {
+      it(`when npm_config_loglevel is set to ${log}`, () => {
+        global.process.env = {npm_config_loglevel: log}
+        require('./index');
+        expect(global.console.log).not.toHaveBeenCalled();
+      });
+    });
+  });
+});