Rewrite levels

Wakaru uses standard by default. Change the level when you want to stay closer to the input's behavior or try stronger recovery.

Choosing a level

npx wakaru input.js --level minimal
npx wakaru input.js                     # standard is the default
npx wakaru input.js --level aggressive

See the difference

Consider a function that reads a user's name or falls back to "Anonymous":

function displayName(user) {
    return user.name != null ? user.name : "Anonymous";
}

With minimal, Wakaru keeps the two property reads:

function displayName(user) {
    if (user.name != null) {
        return user.name;
    }
    return "Anonymous";
}

With standard, it recovers nullish coalescing:

function displayName(user) {
    return user.name ?? "Anonymous";
}

For a plain object such as { name: "Ada" }, both return "Ada". The difference matters when name is a getter: the first version reads it twice when the value is present, while the second reads it once. A getter can have side effects or return a different value on each read.

Try each version separately with this user:

let reads = 0;
const user = {
    get name() {
        reads += 1;
        return reads === 1 ? "Ada" : "Grace";
    }
};

console.log(displayName(user)); // minimal: "Grace", standard: "Ada"

In minimal, the condition reads "Ada", then the return reads "Grace". In standard, ?? reads "Ada" once and returns it.

minimal preserves that behavior. standard favors the familiar ?? form, assuming the property is stable and reading it has no side effects. aggressive produces the same result as standard in this example. A higher level does not always change the output.

You can compare levels on your own code in the playground. The full rewrite assumptions explain the recovery choices each level permits.

Dead code

Dead-code removal is a separate choice. By default, Wakaru removes only the dead code its own transforms create. Dead code that already existed in the input stays. Opt into a full reachability sweep with:

npx wakaru input.js --dce