Read a query string

A web address can end with a query string such as color=red&size=m&size=l. It holds pairs of a name and a value. A & separates the pairs. An = separates the name from the value.

Write parseQuery(text). It returns an object.

• Each name is a key.
• A name that appears once has a string value. "a=1" gives { a: "1" }.
• A name that appears more than once has an array of strings, in the order of the text.
• A pair with no = has the value "".
• Split each pair at the first =. Later = characters belong to the value.
• Skip empty pairs. The text "a=1&&b=2" has an empty pair between the two &.
• Decode every name and every value. A + stands for a space. A % with two hex digits, such as %20 or %C3%A9, stands for a character. Replace each + with a space first, and then use decodeURIComponent.
• All % codes in the tests are valid.
• An empty text gives an empty object.

Examples

Call	Result
parseQuery('color=red&size=m&size=l')	{ color: 'red', size: ['m', 'l'] }
parseQuery('q=hello+world')	{ q: 'hello world' }
parseQuery('')	{}