Method run

src/core/runtime/reactivity.js:91–143

* Re-evaluate expression with dependency tracking, compare with last * value, and call handler if changed. Returns false if circular * guard tripped (caller should skip this effect). * @returns {boolean} Whether the effect ran successfully

()

     * @returns {boolean} Whether the effect ran successfully
     */
    run() {
        this._consecutiveTriggers++;
        if (this._consecutiveTriggers > 100) {
            console.error(
                "Reactivity loop detected: an effect triggered 100 consecutive " +
                "times without settling. This usually means an effect is modifying " +
                "a variable it also depends on.",
                this.element || this
            );
            return false;
        }

        var reactivity = this._reactivity;

        // Unsubscribe from current deps
        reactivity._unsubscribeEffect(this);

        // Re-run expression with tracking
        var oldDeps = this.dependencies;
        this.dependencies = new Map();

        var prev = reactivity._currentEffect;
        reactivity._currentEffect = this;
        var newValue;
        try {
            newValue = this.expression();
        } catch (e) {
            console.error("Error in reactive expression:", e);
            // Restore old dependencies on error
            this.dependencies = oldDeps;
            reactivity._currentEffect = prev;
            reactivity._subscribeEffect(this);
            return true;
        }
        reactivity._currentEffect = prev;

        // Subscribe to new deps
        reactivity._subscribeEffect(this);

        // Clean up empty subscription entries for deps that were dropped
        reactivity._cleanupOrphanedDeps(oldDeps);

        // Compare and fire (Object.is semantics: NaN === NaN, +0 !== -0)
        if (!_sameValue(newValue, this._lastValue)) {
            this._lastValue = newValue;
            try {
                this.handler(newValue);
            } catch (e) {
                console.error("Error in reactive handler:", e);
            }
        }
        return true;
    }

    /** Reset circular guard after cascade settles. */
    resetTriggerCount() {