diff --git a/src/__snapshots__/index.spec.js.snap b/src/__snapshots__/index.spec.js.snap
index a0937f0..6d41920 100644
--- a/src/__snapshots__/index.spec.js.snap
+++ b/src/__snapshots__/index.spec.js.snap
@@ -225,3 +225,13 @@ function logAll() {
 }
 "
 `;
+
+exports[`12. Merge options - fix #12 1`] = `
+"
+console.log(a);
+
+      ↓ ↓ ↓ ↓ ↓ ↓
+
+console.log(\\"unknown(1:0)\\", \\"a\\", a);
+"
+`;
diff --git a/src/index.js b/src/index.js
index f1db4f7..a849f2e 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,10 +1,4 @@
-const defaultSettings = {
-  injectScope: true,
-  injectVariableName: true,
-  injectFileName: true,
-};
-
-const defaultMethods = ['debug', 'error', 'exception', 'info', 'log', 'warn'];
+import { buildOptions } from './utils/pluginOptions';
 
 const idNameSelector = path => path.node.id.name;
 const keyNameSelector = path => path.node.key.name;
@@ -35,7 +29,8 @@ export default function({ types: t }) {
         if (!looksLike(path.node, { name: 'console' })) {
           return;
         }
-        const settings = buildSettings(opts || {});
+        // find somewhere we can move this so that it only needs to be called once.
+        const settings = buildOptions(opts || {});
         const parentCallExp = path.findParent(t.isCallExpression);
         if (isTrackingConsoleCallStatement(path, parentCallExp, settings)) {
           callExpressions.add(parentCallExp);
@@ -43,7 +38,7 @@ export default function({ types: t }) {
       },
       Program: {
         exit(_, { file, opts }) {
-          const settings = buildSettings(opts || {});
+          const settings = buildOptions(opts || {});
           callExpressions.forEach(callExp => {
             if (!callExp || evaluatedExpressions.has(callExp)) {
               return;
@@ -100,20 +95,6 @@ export default function({ types: t }) {
     }, []);
   }
 
-  function buildSettings(opts) {
-    // remove ignore patterns from settings since it has been consumed already
-    // eslint-disable-next-line no-unused-vars
-    const { methods, ignorePatterns, ...flags } = opts;
-    // output spreads the flags over each method
-    // in the future this could be expanded to allow method level config
-    return (methods || defaultMethods).reduce((acc, curr) => {
-      return {
-        ...acc,
-        [curr]: Object.values(flags).length ? flags : defaultSettings,
-      };
-    }, {});
-  }
-
   function findCallScope(path, scope = []) {
     const parentFunc = path.findParent(path =>
       Object.keys(scopeHandlers).includes(path.type)
diff --git a/src/index.spec.js b/src/index.spec.js
index 30426c4..e00902b 100644
--- a/src/index.spec.js
+++ b/src/index.spec.js
@@ -81,5 +81,10 @@ pluginTester({
         methods: ['debug', 'log', 'info'],
       },
     },
+    {
+      title: 'Merge options - fix #12',
+      code: `console.log(a);`,
+      pluginOptions: { injectScope: false },
+    },
   ],
 });
diff --git a/src/utils/__snapshots__/pluginOptions.spec.js.snap b/src/utils/__snapshots__/pluginOptions.spec.js.snap
new file mode 100644
index 0000000..1f1e0f7
--- /dev/null
+++ b/src/utils/__snapshots__/pluginOptions.spec.js.snap
@@ -0,0 +1,186 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`buildOptions should allow methods to be changed 1`] = `
+Object {
+  "debug": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+}
+`;
+
+exports[`buildOptions should overwrite defaults 1`] = `
+Object {
+  "debug": Object {
+    "injectFileName": false,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "error": Object {
+    "injectFileName": false,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "exception": Object {
+    "injectFileName": false,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "info": Object {
+    "injectFileName": false,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "log": Object {
+    "injectFileName": false,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "warn": Object {
+    "injectFileName": false,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+}
+`;
+
+exports[`buildOptions should return defaults for invalid args 1`] = `
+Object {
+  "debug": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "error": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "exception": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "info": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "log": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "warn": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+}
+`;
+
+exports[`buildOptions should return defaults for invalid args 2`] = `
+Object {
+  "debug": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "error": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "exception": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "info": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "log": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "warn": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+}
+`;
+
+exports[`buildOptions should return defaults for invalid args 3`] = `
+Object {
+  "debug": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "error": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "exception": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "info": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "log": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "warn": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+}
+`;
+
+exports[`buildOptions should return defaults for invalid args 4`] = `
+Object {
+  "debug": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "error": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "exception": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "info": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "log": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+  "warn": Object {
+    "injectFileName": true,
+    "injectScope": true,
+    "injectVariableName": true,
+  },
+}
+`;
diff --git a/src/utils/index.js b/src/utils/index.js
new file mode 100644
index 0000000..e69de29
diff --git a/src/utils/pluginOptions.js b/src/utils/pluginOptions.js
new file mode 100644
index 0000000..9fa0175
--- /dev/null
+++ b/src/utils/pluginOptions.js
@@ -0,0 +1,36 @@
+const defaultSettings = {
+  injectScope: true,
+  injectVariableName: true,
+  injectFileName: true,
+};
+
+const defaultMethods = ['debug', 'error', 'exception', 'info', 'log', 'warn'];
+
+// this should deep merge in the furture when we are dealing with more than just flags
+const mergeOptions = options => {
+  const sanitizedOptions = Object.keys(options || {})
+    .filter(key => Object.keys(defaultSettings).includes(key))
+    .reduce(
+      (acc, key) => ({
+        ...acc,
+        [key]: options[key],
+      }),
+      {}
+    );
+  return Object.assign({}, defaultSettings, sanitizedOptions);
+};
+
+export const buildOptions = userOptions => {
+  // remove ignore patterns from settings since it has been consumed already
+  // eslint-disable-next-line no-unused-vars
+  const { methods, ignorePatterns, ...options } = userOptions || {};
+
+  // output spreads the flags over each method
+  // in the future this could be expanded to allow method level config
+  return (methods || defaultMethods).reduce((acc, method) => {
+    return {
+      ...acc,
+      [method]: mergeOptions(options),
+    };
+  }, {});
+};
diff --git a/src/utils/pluginOptions.spec.js b/src/utils/pluginOptions.spec.js
new file mode 100644
index 0000000..0ca9d52
--- /dev/null
+++ b/src/utils/pluginOptions.spec.js
@@ -0,0 +1,24 @@
+import { buildOptions } from './pluginOptions';
+
+describe('buildOptions', () => {
+  test('should return defaults for invalid args', () => {
+    let actual = buildOptions();
+    expect(actual).toMatchSnapshot();
+    actual = buildOptions(undefined);
+    expect(actual).toMatchSnapshot();
+    actual = buildOptions({});
+    expect(actual).toMatchSnapshot();
+    actual = buildOptions({ unknownFlag: false });
+    expect(actual).toMatchSnapshot();
+  });
+
+  test('should allow methods to be changed', () => {
+    let actual = buildOptions({ methods: ['debug'] });
+    expect(actual).toMatchSnapshot();
+  });
+
+  test('should overwrite defaults', () => {
+    let actual = buildOptions({ injectFileName: false });
+    expect(actual).toMatchSnapshot();
+  });
+});