unicorn/max-nested-calls

Nested calls run from the inside out, so you read save(normalize(parse(read(file)))) backwards, counting parentheses on the way. Past a few levels, the code is easier to follow if you put a step in the middle into a well-named variable.

A call counts as nested when it's in an argument of another call or of a new expression. By default up to 3 levels are allowed, and each deeper call is reported.

Configure#

Off by default. To turn it on:

bunfig.toml

[lint.rules]
"unicorn/max-nested-calls" = "error" # or "warn"

Every option, set to its default:

bunfig.toml

[lint.rules]
"unicorn/max-nested-calls" = ["error", {
  max = 3,
}]

Examples#

example.js1 problem

save(normalize(parse(read(file))));

example.jsNo problems

const config = parse(read(file));
save(normalize(config));

A method chain isn't nesting:

example.jsNo problems

const total = text.trim().split(",").map(Number).filter(Boolean).reduce(add);

The count starts again inside a function, a class or JSX:

example.jsNo problems

schedule(retry(withTimeout(() => save(normalize(config)))));

Options#

Option	Default	What it does
`max`	`3`	The deepest nesting that's allowed.

example.jswith { "max": 2 }1 problem

save(normalize(parse(text)));

example.jswith { "max": 4 }No problems

save(normalize(parse(read(file))));