unicorn/prefer-single-call

push(), unshift(), classList.add(), classList.remove() and importScripts() take any number of arguments. Two calls in a row on the same object do the same thing as one call, with more lines.

--fix merges two push() or unshift() calls if the file shows that the object is an array: a variable that's declared with [], new Array(), Array.from() or Array.of() and never assigned again. Other objects have a push() too. The second argument of a stream's push() is the encoding. The arguments have to be plain values, because rows.push(nextId()) can depend on the push() before it. It merges two importScripts() calls if the arguments are strings.

--fix-dangerously merges the other calls as well. No flag merges them when there's a comment between them, or when one of the second call's arguments reads the object, as in items.push(items.length).

Configure#

Off by default. To turn it on:

[lint.rules]
"unicorn/prefer-single-call" = "error" # or "warn"

Every option, set to its default:

[lint.rules]
"unicorn/prefer-single-call" = ["error", {
  ignore = [], # list of strings
}]

Examples#

errors.push("name is required");
errors.push("email is not valid");

queue.unshift(second);
queue.unshift(first);

button.classList.add("active");
button.classList.add("large");

importScripts("parser.js");
importScripts("worker-utils.js");

errors.push("name is required", "email is not valid");

queue.unshift(first, second);

button.classList.add("active", "large");

importScripts("parser.js", "worker-utils.js");

push() on a stream is a different method that takes one chunk. push() and unshift() are never reported on stream, this, this.stream, process.stdin, process.stdout and process.stderr:

stream.push(header);
stream.push(body);

Options#

readable.push(header);
readable.push(body);

readable.push(header);
readable.push(body);