getTarget (name, flowId) {
                /** @type {[LinkTarget]} */
                let possibleTargets = this.getTargets(name)
                /** @type {LinkTarget} */
                let target
                if (possibleTargets.length && flowId) {
                    possibleTargets = possibleTargets.filter(e => e.flowId === flowId)
                }
                if (possibleTargets.length === 1) {
                    target = possibleTargets[0]
                }
                return target
            }
Get a single target by registered name.
To restrict to a single flow, include the `flowId`
If there is no targets OR more than one target, null is returned
@param {string} name Name of the node
@param {string} [flowId]
@returns {LinkTarget} target