Add option to allow coercion of array items

Fixes #6

index.js

@@ -51,7 +51,23 @@ function parse (args, opts) {
   var negative = /^-[0-9]+(\.[0-9]+)?/
   var negatedBoolean = new RegExp('^--' + configuration['negation-prefix'] + '(.+)')
 
-  ;[].concat(opts.array).filter(Boolean).forEach(function (key) {
+  ;[].concat(opts.array).filter(Boolean).forEach(function (opt) {
+    var key = opt.key || opt
+
+    // assign to flags[bools|strings|numbers]
+    const assignment = Object.keys(opt).map(function (key) {
+      return ({
+        boolean: 'bools',
+        string: 'strings',
+        number: 'numbers'
+      })[key]
+    }).filter(Boolean).pop()
+
+    // assign key to be coerced
+    if (assignment) {
+      flags[assignment][key] = true
+    }
+
     flags.arrays[key] = true
     flags.keys.push(key)
   })

test/yargs-parser.js

@@ -1529,6 +1529,31 @@ describe('yargs-parser', function () {
       var result = parser(['-x', 'val1', '-x', 'val1'])
       result.should.have.property('x').that.is.an('array').and.to.deep.equal(['val1', 'val1'])
     })
+
+    // see https://github.com/yargs/yargs-parser/issues/6
+    it('should respect the type `boolean` option for arrays', function () {
+      var result = parser(['-x=true', 'false'], {
+        array: [{key: 'x', boolean: true}]
+      })
+      result.should.have.property('x').that.is.an('array').and.to.deep.equal([true, false])
+    })
+
+    it('should respect the type `number` option for arrays', function () {
+      var result = parser(['-x=5', '2'], {
+        array: [{key: 'x', number: true}]
+      })
+      result.should.have.property('x').that.is.an('array').and.to.deep.equal([5, 2])
+    })
+
+    it('should respect the type `string` option for arrays', function () {
+      var result = parser(['-x=5', '2'], {
+        configuration: {
+          'parse-numbers': true
+        },
+        array: [{key: 'x', string: true}]
+      })
+      result.should.have.property('x').that.is.an('array').and.to.deep.equal(['5', '2'])
+    })
   })
 
   describe('nargs', function () {