gnome-shell/js/misc/params.js
Dan Winship e9e2786fa3 [Params] always return a new object from Params.parse
Rather than returning a modified copy of the input params/defaults,
always return a new object, copying the appropriate values into it.

https://bugzilla.gnome.org/show_bug.cgi?id=608667
2010-05-03 12:51:09 -04:00

35 lines
1.1 KiB
JavaScript

/* -*- mode: js2; js2-basic-offset: 4; indent-tabs-mode: nil -*- */
// parse:
// @params: caller-provided parameter object, or %null
// @defaults: function-provided defaults object
// @allowExtras: whether or not to allow properties not in @default
//
// Examines @params and fills in default values from @defaults for
// any properties in @defaults that don't appear in @params. If
// @allowExtras is not %true, it will throw an error if @params
// contains any properties that aren't in @defaults.
//
// If @params is %null, this returns the values from @defaults.
//
// Return value: a new object, containing the merged parameters from
// @params and @defaults
function parse(params, defaults, allowExtras) {
let ret = {}, prop;
if (!params)
params = {};
for (prop in params) {
if (!(prop in defaults) && !allowExtras)
throw new Error('Unrecognized parameter "' + prop + '"');
ret[prop] = params[prop];
}
for (prop in defaults) {
if (!(prop in params))
ret[prop] = defaults[prop];
}
return ret;
}