feat(parser): convert "true" and "false" to booleans

BREAKING CHANGE: This will convert strings "true" and "false" to
booleans, they will no longer be evaluated as strings.

README.md

@@ -23,6 +23,8 @@ useful when building an API and accepting various user specificed queries.
   * `$nin`
   * `$exists`
   * `$regex`
+* Parse string integers and floats to numbers
+* Parse string boolean to ture/false booleans
 
 | operation | query string  | query object |
 |-----------|---------------|--------------|

index.js

@@ -101,7 +101,11 @@ module.exports.prototype.customAfter = function(field) {
 };
 
 module.exports.prototype.parseString = function(string) {
-  if (!isNaN(string)) {
+  if (string.toLowerCase() === 'true') {
+    return true;
+  } else if (string.toLowerCase() === 'false') {
+    return false;
+  } else if (!isNaN(string)) {
     return parseFloat(string, 10);
   } else {
     return string;

test.js

@@ -100,6 +100,32 @@ describe('customAfter()', function() {
   });
 });
 
+describe('parseString()', function() {
+  it('returns boolean true for "true" string', function() {
+    assert.equal(qs.parseString('true'), true);
+  });
+
+  it('returns boolean false for "flase" string', function() {
+    assert.equal(qs.parseString('false'), false);
+  });
+
+  it('returns number for parseable integer', function() {
+    assert.equal(qs.parseString('100'), 100);
+  });
+
+  it('returns number for zero padded parseable integer', function() {
+    assert.equal(qs.parseString('000100'), 100);
+  });
+
+  it('returns number for parseable float', function() {
+    assert.equal(qs.parseString('10.123'), 10.123);
+  });
+
+  it('returns number for zero padded parseable float', function() {
+    assert.equal(qs.parseString('00010.123'), 10.123);
+  });
+});
+
 describe('parse()', function() {
   describe('parsing', function() {
     describe('key value validation', function() {
@@ -143,6 +169,17 @@ describe('parse()', function() {
         });
       });
 
+      it('return string boolean as boolean', function() {
+        query = qs.parse({
+          foo: 'true',
+          bar: 'false'
+        });
+        assert.deepEqual(query, {
+          foo: true,
+          bar: false
+        });
+      });
+
       it('returns string integer as number', function() {
         query = qs.parse({
           navn: '10'
@@ -185,6 +222,17 @@ describe('parse()', function() {
         });
       });
 
+      it('return string boolean as boolean', function() {
+        query = qs.parse({
+          foo: '!true',
+          bar: '!false'
+        });
+        assert.deepEqual(query, {
+          foo: {$ne: true},
+          bar: {$ne: false}
+        });
+      });
+
       it('returns string integer as number', function() {
         query = qs.parse({
           navn: '!10'