Call expression arguments formatting

[MichaReiser]

Prettier has sophisticated formatting for call arguments that prevents unnecessary line breaks. For example, it formats the following snipped without breaking the passed arrow function over multiple lines (except the body).

// Grouped if less than 3 arguments
testMethod(() => {
  expected(() =>
    moduleMocker.generateFromMetadata(moduleMocker.getMetadata(/a/))
  ).not.toThrow();
}, "string");

// Prettier:
// Grouped if less than 3 arguments
testMethod(() => {
  expected(() => moduleMocker.generateFromMetadata(moduleMocker.getMetadata(/a/))).not.toThrow();
}, "string");

Relevant test cases:

• arrow/call.js
• break-call/react.js
• last-argument/expensions/empty-lines.js
• preserve-line/argument-list.js
• js/functional-composition/functional_compose.js

Expected

Output matches Prettier's output (or closely)

[ematipico]

We need to study prettier' source and see what they are doing. They use Alternatives for their solution. So probably we should wait until we have a better IR that matches prettier's.

[ematipico]

I am going to a look at this now