google/closure-compiler

Compress condition as logical expression

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#1842 opened on Jun 13, 2016

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 (3 comments) (0 reactions) (0 assignees)Java (7,176 stars) (1,197 forks)batch import
enhancementhelp wanted

Description

Hi,

I wonder if it's possible to shrink an expression like

if (!a)
   c = b;
else
   c =a;

to

c = a || b;

instead of

c = a ? a : b;

You do such tricks already in a logical manner to kick out if-statements, but it would make sense within expressions as well. Or do I miss something, that it should be avoided?

Thanks!

Contributor guide

Tech stack
javascriptjava
Domain
toolingperformance
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
JavaAST transformation
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
35
Research direction
This issue requests a new optimization to convert if else assignments to logical OR expressions. To implement, examine existing similar patterns in the Closure Compiler's peephole optimizations, such as the transformation from ternary (a ? a : b) to OR (a || b) or other if to expression conversions. The discussion in the issue (comments) and related code in the PeepholeMinimizeConditions.java or similar files should be reviewed. The research should understand why the current behavior uses ternary and whether using logical OR is always safe (e.g., with side effects).