gnome-shell/js/misc/params.js
2010-02-02 10:31:38 -05:00

33 lines
1002 B
JavaScript

/* -*- mode: js2; js2-basic-offset: 4; indent-tabs-mode: nil -*- */
// parse:
// @params: caller-provided parameter object, or %null
// @default: 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 @defaults.
//
// Return value: the updated params
function parse(params, defaults, allowExtras) {
if (!params)
return defaults;
if (!allowExtras) {
for (let prop in params) {
if (!(prop in defaults))
throw new Error('Unrecognized parameter "' + prop + '"');
}
}
for (let prop in defaults) {
if (!(prop in params))
params[prop] = defaults[prop];
}
return params;
}