Warn about common option misspellings (#6489)

* chore(tests): add failing tests for baseUrl

* chore(tests): simplify to just warning

* feat: warn about likely-misspelled options

* chore: add semi-colon

* chore: add missing semi-colons

---------

Co-authored-by: Ell Bradshaw <ell@c9a.co>
Co-authored-by: Jay <jasonsaayman@gmail.com>

lib/core/Axios.js

@@ -97,6 +97,11 @@ class Axios {
       }
     }
 
+    validator.assertOptions(config, {
+      baseUrl: validators.spelling('baseURL'),
+      withXsrfToken: validators.spelling('withXSRFToken')
+    }, true);
+
     // Set config.method
     config.method = (config.method || this.defaults.method || 'get').toLowerCase();
 

lib/helpers/validator.js

@@ -52,6 +52,14 @@ validators.transitional = function transitional(validator, version, message) {
   };
 };
 
+validators.spelling = function spelling(correctSpelling) {
+  return (value, opt) => {
+    // eslint-disable-next-line no-console
+    console.warn(`${opt} is likely a misspelling of ${correctSpelling}`);
+    return true;
+  }
+};
+
 /**
  * Assert object's properties type
  *

test/specs/options.spec.js

@@ -71,6 +71,22 @@ describe('options', function () {
     });
   });
 
+  it('should warn about baseUrl', function (done) {
+    spyOn(window.console, 'warn');
+
+    const instance = axios.create({
+      baseUrl: 'http://example.com/'
+    });
+
+    instance.get('/foo');
+
+    getAjaxRequest().then(function (request) {
+      expect(window.console.warn).toHaveBeenCalledWith('baseUrl is likely a misspelling of baseURL');
+      expect(request.url).toBe('/foo');
+      done();
+    });
+  });
+
   it('should ignore base URL if request URL is absolute', function (done) {
     const instance = axios.create({
       baseURL: 'http://someurl.com/'