diff --git a/opter.js b/opter.js
index cab68c7..32e29a1 100644
--- a/opter.js
+++ b/opter.js
@@ -15,6 +15,7 @@ const defaultErrorMessages = {
   tooManyArguments: (optionName) => `Too many arguments for option ${optionName}`,
 }
 
+// TODO figure out how to avoid having to use '<options>.opts to access the output of this'
 
 module.exports = class Opts {
   constructor(argv) {
@@ -73,6 +74,7 @@ module.exports = class Opts {
    **/
   requireOptionArgument(nameWithDashes, minRequired=1, maxRequired=1, tooFewMessage=null, tooManyMessage=null) {
     let name = stripDashes(nameWithDashes);
+    // FIXME have to check synonyms, too
     if (name in this.opts) {
       console.log('type', typeof this.opts[name] === 'boolean');
       console.log(this.opts[name]);
@@ -86,6 +88,14 @@ module.exports = class Opts {
     }
     return true;
   }
+
+  contains(nameWithDashes) {
+    const name = stripDashes(nameWithDashes);
+    console.log('synonyms:', this.synonyms);
+    if (name in this.opts) return true;
+    if (name in this.synonyms) return true;
+    return false;
+  }
 }
 
 /**
diff --git a/test.js b/test.js
index f6f0e38..85c1265 100644
--- a/test.js
+++ b/test.js
@@ -8,9 +8,10 @@ const Opter = require('./opter.js');
 
 const opts = new Opter(process.argv)
 opts.synonymize('-i', '--input');
+opts.synonymize('-d', '--debug');
 opts.requireOption('-i');
 opts.requireOptionArgument('-i');
-console.log(opts.opts);
+console.log('contains', opts.contains('-d'));
 
 // const _defaultErrorMessages = {
 //   missingRequiredOption: (optionName) => `Missing required option '${optionName}'`,