{"id":153,"date":"2021-09-10T13:21:09","date_gmt":"2021-09-10T13:21:09","guid":{"rendered":"http:\/\/www.clientcyde.com\/?p=153"},"modified":"2021-09-10T13:24:46","modified_gmt":"2021-09-10T13:24:46","slug":"extract-function-arguments-and-defaults-when-using-object-destructuring","status":"publish","type":"post","link":"https:\/\/www.clientcyde.com\/?p=153","title":{"rendered":"Extract function arguments and defaults when using object destructuring"},"content":{"rendered":"\n

This was such a pain to get working, and the solution isn’t ideal but it works. <\/p>\n\n\n\n

I wanted to create an extensible library of functions which could be displayed in a UI. So I created functions like this:<\/p>\n\n\n\n

function myFunction({a = '1', b = 2, c = [1,2], d = function(){return 'hi'}} = {}){};<\/code><\/pre>\n\n\n\n
To display the function options in a UI to allow users to call them, I wanted to get all the parameters and their defaults (and not pollute the global scope).  I thought it’d be easy.  It was not.  This is my solution:<\/p>\n\n\n\n
function getArguments(f) {\n  var t = {};\n  (new Function(`with(this) {\n    with(new Proxy(this,{\n      has(t, p) {return true;},\n      get(t, p) {return (p in t ? t : window)[p]}\n    })) {\n      ${f.toString().match(\/^function\\s*[^(]*\\(\\s*{(.*)}\\s*=\\s*{}\/ms)[1]}\n    }\n  }`)).call(t);\n  return Object.entries(t).map(v => ({name: v[0], value: v[1]}))\n}\n<\/code><\/pre>\n\n\n\n
So you can call it like this:<\/p>\n\n\n\n
getArguments(myFunction);<\/code><\/pre>\n\n\n\n
And it returns all the arguments and their default values:<\/p>\n\n\n\n
\"\"<\/a><\/figure>\n\n\n\n
Note: it only returns arguments which have defaults. <\/p>\n","protected":false},"excerpt":{"rendered":"
This was such a pain to get working, and the solution isn’t ideal but it works. I wanted to create an extensible library of functions which could be displayed in a UI. So I created functions like this: To display the function options in a UI to allow users to call them, I wanted to … Continue reading Extract function arguments and defaults when using object destructuring<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[30,27],"tags":[],"class_list":["post-153","post","type-post","status-publish","format-standard","hentry","category-javascript","category-webdev"],"_links":{"self":[{"href":"https:\/\/www.clientcyde.com\/index.php?rest_route=\/wp\/v2\/posts\/153","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.clientcyde.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.clientcyde.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.clientcyde.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.clientcyde.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=153"}],"version-history":[{"count":3,"href":"https:\/\/www.clientcyde.com\/index.php?rest_route=\/wp\/v2\/posts\/153\/revisions"}],"predecessor-version":[{"id":158,"href":"https:\/\/www.clientcyde.com\/index.php?rest_route=\/wp\/v2\/posts\/153\/revisions\/158"}],"wp:attachment":[{"href":"https:\/\/www.clientcyde.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=153"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.clientcyde.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=153"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.clientcyde.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=153"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}