diff --git a/index.js b/index.js
index 997bad5..c4274ae 100644
--- a/index.js
+++ b/index.js
@@ -32,6 +32,41 @@ function getMainArgs() {
   return process.argv.slice(2);
 }
 
+function setOptionValue(parseOptions, option, value, result) {
+  const multiple = parseOptions.multiples &&
+    parseOptions.multiples.includes(option);
+  const withValue = parseOptions.withValue &&
+    parseOptions.withValue.includes(option);
+
+  // Normal flag: !withValue && value === undefined
+  // Normal value, withValue && value !== undefined
+  // Special case: withValue && value === undefined
+  //    store as normal for withValue with value undefined
+  // Special case: !withValue && value !== undefined
+  //    store as normal for withValue (and not a flag)
+
+  // Flags
+  // Only mark flags for plain flag without a value, expected or otherwise.
+  const isFlag = !withValue && value === undefined;
+  if (isFlag)
+    result.flags[option] = true;
+
+  // Values
+  if (multiple) {
+    // Always store value in array, including for flags.
+    // result.values[option] starts out not present,
+    // first value is added as new array [val],
+    // subsequent values are pushed to existing array.
+    const val = isFlag ? true : value;
+    if (result.values[option] !== undefined)
+      result.values[option].push(val);
+    else
+      result.values[option] = [val];
+  } else if (!isFlag) {
+    result.values[option] = value;
+  }
+}
+
 const parseArgs = (
   argv = getMainArgs(),
   options = {}
@@ -66,61 +101,28 @@ const parseArgs = (
       arg = arg.slice(2); // remove leading --
 
       if (arg.includes('=')) {
-        // withValue equals(=) case
-        const argParts = arg.split('=');
-
-        result.flags[argParts[0]] = true;
-        // If withValue option is specified, take 2nd part after '=' as value,
-        // else set value as undefined
-        const val = options.withValue &&
-          options.withValue.includes(argParts[0]) ?
-          argParts[1] : undefined;
-        // Append value to previous values array for case of multiples
-        // option, else add to empty array
-        result.values[argParts[0]] = [].concat(
-          options.multiples &&
-            options.multiples.includes(argParts[0]) &&
-            result.values[argParts[0]] || [],
-          val,
-        );
+        const index = arg.indexOf('=');
+        setOptionValue(options,
+                       arg.slice(0, index), arg.slice(index + 1), result);
       } else if (pos + 1 < argv.length && !argv[pos + 1].startsWith('-')) {
         // withValue option should also support setting values when '=
         // isn't used ie. both --foo=b and --foo b should work
 
-        result.flags[arg] = true;
-        // If withValue option is specified, take next position arguement as
+        // If withValue option is specified, take next position argument as
         // value and then increment pos so that we don't re-evaluate that
         // arg, else set value as undefined ie. --foo b --bar c, after setting
         // b as the value for foo, evaluate --bar next and skip 'b'
         const val = options.withValue && options.withValue.includes(arg) ?
           argv[++pos] :
           undefined;
-        // Append value to previous values array for case of multiples
-        // option, else add to empty array
-        result.values[arg] = [].concat(
-          options.multiples && options.multiples.includes(arg) &&
-            result.values[arg] ?
-            result.values[arg] :
-            [],
-          val);
+        setOptionValue(options, arg, val, result);
       } else {
-        // Cases when an arg is specified without a value, example
-        // '--foo --bar' <- 'foo' and 'bar' flags should be set to true and
-        // shave value as undefined
-        result.flags[arg] = true;
-        // Append undefined to previous values array for case of
-        // multiples option, else add to empty array
-        result.values[arg] = [].concat(
-          options.multiples && options.multiples.includes(arg) &&
-            result.values[arg] ?
-            result.values[arg] :
-            [],
-          undefined
-        );
+        // No argument available as a value.
+        setOptionValue(options, arg, undefined, result);
       }
 
     } else {
-      // Arguements without a dash prefix are considered "positional"
+      // Arguments without a dash prefix are considered "positional"
       result.positionals.push(arg);
     }
 
diff --git a/test/index.js b/test/index.js
index 36eb4c6..604ee30 100644
--- a/test/index.js
+++ b/test/index.js
@@ -17,7 +17,7 @@ test('Everything after a bare `--` is considered a positional argument', functio
 
 test('args are true', function (t) {
   const passedArgs = ['--foo', '--bar']
-  const expected = { flags: { foo: true, bar: true}, values: {foo: [undefined], bar: [undefined]}, positionals: [] }
+  const expected = { flags: { foo: true, bar: true}, values: {}, positionals: [] }
   const args = parseArgs(passedArgs)
 
   t.deepEqual(args, expected, 'args are true')
@@ -27,7 +27,7 @@ test('args are true', function (t) {
 
 test('arg is true and positional is identified', function (t) {
   const passedArgs = ['--foo=a', '--foo', 'b']
-  const expected = { flags: { foo: true}, values: { foo: [undefined]}, positionals: ['b'] }
+  const expected = { flags: { foo: true}, values: { foo: 'a'}, positionals: ['b'] }
   const args = parseArgs(passedArgs)
 
   t.deepEqual(args, expected, 'arg is true and positional is identified')
@@ -38,7 +38,7 @@ test('arg is true and positional is identified', function (t) {
 test('args equals are passed "withValue"', function (t) {
   const passedArgs = ['--so=wat']
   const passedOptions = { withValue: ['so'] }
-  const expected = { flags: { so: true}, values: { so: ["wat"]}, positionals: [] }
+  const expected = { flags: {}, values: { so: "wat" }, positionals: [] }
   const args = parseArgs(passedArgs, passedOptions)
 
   t.deepEqual(args, expected, 'arg value is passed')
@@ -46,10 +46,42 @@ test('args equals are passed "withValue"', function (t) {
   t.end()
 })
 
+test('when zero config option with equals then option treated as withValue', function (t) {
+  const passedArgs = ['--so=wat'];
+  const expected = { flags: {}, values: { so: "wat" }, positionals: [] };
+  const args = parseArgs(passedArgs);
+
+  t.deepEqual(args, expected);
+
+  t.end();
+});
+
+test('when option in withValue is followed by option instead of value then value is undefined', function (t) {
+  const passedArgs = ['--foo', '--bar'];
+  const passedOptions = { withValue: ['foo'] };
+  const expected = { flags: { 'bar': true }, values: { foo: undefined }, positionals: [] };
+  const args = parseArgs(passedArgs, passedOptions);
+
+  t.deepEqual(args, expected);
+
+  t.end();
+});
+
+test('when option=a=b (value includes =) then value is what follows first =', function (t) {
+  const passedArgs = ['--foo=b=ar'];
+  const passedOptions = { withValue: ['foo'] };
+  const expected = { flags: {}, values: { foo: 'b=ar' }, positionals: [] };
+  const args = parseArgs(passedArgs, passedOptions);
+
+  t.deepEqual(args, expected);
+
+  t.end();
+});
+
 test('same arg is passed twice "withValue" and last value is recorded', function (t) {
   const passedArgs = ['--foo=a', '--foo', 'b']
   const passedOptions = { withValue: ['foo'] }
-  const expected = { flags: { foo: true}, values: { foo: ['b']}, positionals: [] }
+  const expected = { flags: {}, values: { foo: 'b' }, positionals: [] }
   const args = parseArgs(passedArgs, passedOptions)
 
   t.deepEqual(args, expected, 'last arg value is passed')
@@ -60,7 +92,7 @@ test('same arg is passed twice "withValue" and last value is recorded', function
 test('args are passed "withValue" and "multiples"', function (t) {
   const passedArgs = ['--foo=a', '--foo', 'b']
   const passedOptions = { withValue: ['foo'], multiples: ['foo'] }
-  const expected = { flags: { foo: true}, values: { foo: ['a', 'b']}, positionals: [] }
+  const expected = { flags: {}, values: { foo: ['a', 'b'] }, positionals: [] }
   const args = parseArgs(passedArgs, passedOptions)
 
   t.deepEqual(args, expected, 'both arg values are passed')
@@ -76,7 +108,7 @@ test('correct default args when use node -p', function(t) {
   const result = parseArgs();
 
   const expected = { flags: { foo: true },
-                     values: { foo: [undefined] },
+                     values: {},
                      positionals: [] };
   t.deepEqual(result, expected);
 
@@ -93,7 +125,7 @@ test('correct default args when use node --print', function(t) {
   const result = parseArgs();
 
   const expected = { flags: { foo: true },
-                     values: { foo: [undefined] },
+                     values: {},
                      positionals: [] };
   t.deepEqual(result, expected);
 
@@ -110,7 +142,7 @@ test('correct default args when use node -e', function(t) {
   const result = parseArgs();
 
   const expected = { flags: { foo: true },
-                     values: { foo: [undefined] },
+                     values: {},
                      positionals: [] };
   t.deepEqual(result, expected);
 
@@ -127,7 +159,7 @@ test('correct default args when use node --eval', function(t) {
   const result = parseArgs();
 
   const expected = { flags: { foo: true },
-                     values: { foo: [undefined] },
+                     values: {},
                      positionals: [] };
   t.deepEqual(result, expected);
 
@@ -144,7 +176,7 @@ test('correct default args when normal arguments', function(t) {
   const result = parseArgs();
 
   const expected = { flags: { foo: true },
-                     values: { foo: [undefined] },
+                     values: {},
                      positionals: [] };
   t.deepEqual(result, expected);
 
@@ -159,7 +191,7 @@ test('excess leading dashes on options are retained', function(t) {
   const passedOptions = { };
   const expected = {
     flags: { '-triple': true },
-    values: { '-triple': [undefined] },
+    values: {},
     positionals: []
   };
   const result = parseArgs(passedArgs, passedOptions);