Function parseUpdate

docs/app/js/sanddance-app.js:146617–146626

* Parse an event-driven operator update.

(spec)

/**
 * Parse an event-driven operator update.
 */ function parseUpdate(spec) {
    var ctx = this, srcid = (0, _vegaUtil.isObject)(srcid = spec.source) ? srcid.$ref : srcid, source = ctx.get(srcid), target = null, update = spec.update, params = undefined;
    if (!source) (0, _vegaUtil.error)("Source not defined: " + spec.source);
    target = spec.target && spec.target.$expr ? ctx.eventExpression(spec.target.$expr) : ctx.get(spec.target);
    if (update && update.$expr) {
        if (update.$params) params = ctx.parseParameters(update.$params);
        update = ctx.handlerExpression(update.$expr);
    }
    ctx.update(spec, source, target, update, params);
}
const SKIP = {
    skip: true
};