urlsearchparams-set.html
<!doctype html>
<html>
<head>
<meta charset="utf8">
<link rel="help" href="http://url.spec.whatwg.org/#dom-urlsearchparams-set">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
test(function() {
var params = new URLSearchParams('a=b&c=d');
params.set('a', 'B');
assert_equals(params + '', 'a=B&c=d');
params = new URLSearchParams('a=b&c=d&a=e');
params.set('a', 'B');
assert_equals(params + '', 'a=B&c=d')
params.set('e', 'f');
assert_equals(params + '', 'a=B&c=d&e=f')
}, 'Set basics');
test(function() {
var params = new URLSearchParams('a=1&a=2&a=3');
assert_true(params.has('a'), 'Search params object has name "a"');
assert_equals(params.get('a'), '1', 'Search params object has name "a" with value "1"');
params.set('first', 4);
assert_true(params.has('a'), 'Search params object has name "a"');
assert_equals(params.get('a'), '1', 'Search params object has name "a" with value "1"');
params.set('a', 4);
assert_true(params.has('a'), 'Search params object has name "a"');
assert_equals(params.get('a'), '4', 'Search params object has name "a" with value "4"');
}, 'URLSearchParams.set');
</script>
</head>
</html>