Deep functions are a Production Risk in JavaScript

Software ResiliencyProgramming Best Practices

Deep functions are a Production Risk in JavaScript

This code insight counts one violation each time an artifact (global function or root code) has a too high depth code. Depth is evaluated throught imbrication of following structures :

if, do, for, while, case,

The depth threshold (max valid depth) is tuned to 5.

Example :
function TooDeepFunction () {

while (toto) { // depth 1
print ‘plouf’;
for (;;) { // depth 2
if (BOOL == 1) { // depth 3
print ‘CAST’;
else if (name = ‘JOHN DOE’) { // else :depth 3, if: depth 4
echo ‘CAST’;
switch (INDEX) { // depth 5
case 1 :
if (BOOL >= 1) { // depth 6 ==> VIOLATION!
print ‘example’;
default :


Why you should care

Having deep functions in Javascript is considered bad practice

Business Impacts

Combining multiple lines of code on one line is risky because it makes the code unreadable and less productive in the long run.

Production Risk

CAST recommendations



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