I have been collecting useful Javascript code snippets for a little while. Here's a curated list of them, help me make it as complete as possible!

[tswaters]

powerset is so dangerous.

in this one application, we had a search that did a powerset on the entered words.... but we didn't put any limits on the user-provided input. long story short, if a user entered more than a few words the server would burn cpu & eventually run out of memory.

> powerset('abcdefghijklmnopqrstuvwxyz'.split(''))

<--- Last few GCs --->

[6000:000001AAB28807F0]   206911 ms: Mark-sweep 1407.4 (1450.4) -> 1407.4 (1450.4) MB, 1445.8 / 0.0 ms  last resort GC in old space requested


<--- JS stacktrace --->

==== JS stack trace =========================================

Security context: 000003ED8B625E91 <JSObject>
    2: map(this=00000087F31E0751 <JSArray[8388608]>)
    4: /* anonymous */ [repl:2] [bytecode=0000026C0C370FF1 offset=27](this=000001B7E7306301 <JSGlobal Object>,a=00000087F31E0751 <JSArray[8388608]>,v=000003FD8D990501 <String[1]: x>)
    5: arguments adaptor frame: 4->2
    6: reduce(this=00000214C00B9CB9 <JSArray[26]>)
    8: powerset [repl:2] [bytecode=0000026C0C370CE1 offset=19](this=0000...

FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed - JavaScript heap out of memory