fix: always store value for a=b (#43)

Co-authored-by: Benjamin E. Coe <bencoe@google.com>

index.js

@@ -8,8 +8,8 @@ const {
   ArrayPrototypePush,
   StringPrototypeCharAt,
   StringPrototypeIncludes,
+  StringPrototypeIndexOf,
   StringPrototypeSlice,
-  StringPrototypeSplit,
   StringPrototypeStartsWith,
 } = require('./primordials');
 
@@ -110,15 +110,16 @@ const parseArgs = (
       arg = StringPrototypeSlice(arg, 2); // remove leading --
 
       if (StringPrototypeIncludes(arg, '=')) {
-        // withValue equals(=) case
-        const argParts = StringPrototypeSplit(arg, '=');
-
-        // If withValue option is specified, take 2nd part after '=' as value,
-        // else set value as undefined
-        const val = options.withValue &&
-          ArrayPrototypeIncludes(options.withValue, argParts[0]) ?
-          argParts[1] : undefined;
-        storeOptionValue(options, argParts[0], val, result);
+        // Store option=value same way independent of `withValue` as:
+        // - looks like a value, store as a value
+        // - match the intention of the user
+        // - preserve information for author to process further
+        const index = StringPrototypeIndexOf(arg, '=');
+        storeOptionValue(
+          options,
+          StringPrototypeSlice(arg, 0, index),
+          StringPrototypeSlice(arg, index + 1),
+          result);
       } else if (pos + 1 < argv.length &&
         !StringPrototypeStartsWith(argv[pos + 1], '-')
       ) {

test/index.js

@@ -47,6 +47,17 @@ test('args equals are passed "withValue"', function(t) {
   t.end();
 });
 
+test('zero config args equals are parsed as if "withValue"', function(t) {
+  const passedArgs = ['--so=wat'];
+  const passedOptions = { };
+  const expected = { flags: { so: true }, values: { so: 'wat' }, positionals: [] };
+  const args = parseArgs(passedArgs, passedOptions);
+
+  t.deepEqual(args, expected, 'arg value is passed');
+
+  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'] };
@@ -58,6 +69,17 @@ test('same arg is passed twice "withValue" and last value is recorded', function
   t.end();
 });
 
+test('args equals pass string including more equals', function(t) {
+  const passedArgs = ['--so=wat=bing'];
+  const passedOptions = { withValue: ['so'] };
+  const expected = { flags: { so: true }, values: { so: 'wat=bing' }, positionals: [] };
+  const args = parseArgs(passedArgs, passedOptions);
+
+  t.deepEqual(args, expected, 'arg value is passed');
+
+  t.end();
+});
+
 test('first arg passed for "withValue" and "multiples" is in array', function(t) {
   const passedArgs = ['--foo=a'];
   const passedOptions = { withValue: ['foo'], multiples: ['foo'] };