{"id":3566,"date":"2025-07-26T02:32:20","date_gmt":"2025-07-26T00:32:20","guid":{"rendered":"https:\/\/blog.tomayac.com\/2025\/07\/26\/what-a-difference-a-semicolon-makes\/"},"modified":"2025-07-26T02:32:20","modified_gmt":"2025-07-26T00:32:20","slug":"what-a-diffrence-a-semicolon-makes","status":"publish","type":"post","link":"https:\/\/tomayac.com\/wordpress\/2025\/07\/26\/what-a-diffrence-a-semicolon-makes\/","title":{"rendered":"What a diff’rence a semicolon makes"},"content":{"rendered":"\n\t\t\t

The other day, I was hit by a baffling TypeError: console.log(...) is not a function<\/code>. Like, WTF \ud83e\udd14? Turns out, I was sloppily adding a quick console.log('here')<\/code> statement for debugging purposes (as one does \ud83d\ude48), which happened to be right before an IIFE<\/a>. I didn't put a ;<\/code>, as it was a throwaway statement I'd remove after finding the bug, but turns out that's the issue. StackOverflow contributor Sebastian Simon<\/a> had the explanation<\/a>:<\/p>\n

\n

It's trying to pass function(){}<\/code> as an argument to the return value of console.log()<\/code> which itself is not a function but actually undefined (check typeof console.log();<\/code>). This is because JavaScript interprets this as console.log()(function(){})<\/code>. console.log<\/code> however is a function.<\/p>\n<\/blockquote>\n

Minimal repro:<\/p>\n

console.<\/span>log<\/span>(<\/span>)<\/span>\n(<\/span>function<\/span>(<\/span>)<\/span>{<\/span>}<\/span>)<\/span><\/code><\/pre>\n
\"Debugged<\/p>\n\n\t\t\t
\n\t\t\t\t\"Thomas\n\t\t\t\tThis post appeared first on https:\/\/blog.tomayac.com\/2025\/07\/26\/what-a-difference-a-semicolon-makes\/<\/a>.\n\t\t\t<\/p>\n\t\t","protected":false},"excerpt":{"rendered":"
\t\t\tThe other day, I was hit by a baffling TypeError: console.log(…) is not a function. Like, WTF \ud83e\udd14? Turns out, I was sloppily adding a quick console.log(‘here’) statement for debugging purposes (as one does \ud83d\ude48), which happened to be right before an I…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"intlwemo_wallet_address":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-3566","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/tomayac.com\/wordpress\/wp-json\/wp\/v2\/posts\/3566","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/tomayac.com\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/tomayac.com\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/tomayac.com\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/tomayac.com\/wordpress\/wp-json\/wp\/v2\/comments?post=3566"}],"version-history":[{"count":1,"href":"https:\/\/tomayac.com\/wordpress\/wp-json\/wp\/v2\/posts\/3566\/revisions"}],"predecessor-version":[{"id":3569,"href":"https:\/\/tomayac.com\/wordpress\/wp-json\/wp\/v2\/posts\/3566\/revisions\/3569"}],"wp:attachment":[{"href":"https:\/\/tomayac.com\/wordpress\/wp-json\/wp\/v2\/media?parent=3566"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/tomayac.com\/wordpress\/wp-json\/wp\/v2\/categories?post=3566"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/tomayac.com\/wordpress\/wp-json\/wp\/v2\/tags?post=3566"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
Andre<\/a> on Mastodon reminded me<\/a> of Chris Coyier<\/a>'s excellent Web Development Merit Badges<\/a>, so I'm now proudly wearing mine: "Debugged something for over one hour where the fix was literally one character"<\/em>:<\/p>\n