LWC Repeating Lighting Layout Items with for:each record set and on-click action not getting ID of item clicked

Question

Primary goal:

• LWC on Campaign Lightning Page (done)
• Get list of Campaign Members from apex wire (done)
• Generate list of Campaign Members on left half of screen using lightning layout items (completed)
• When user clicks one of the people on the left, load a child component on the right side of the screen with that person's details (in progress / stuck)

When clicking on a campaign member (repeated item with for:each key), I can't seem to get the member or member id passed via event (on-click).

The console just shows undefined no matter what variety of target, currentTarget, dataset, detail, etc. I try to use. I've looked at tons of other articles and nothing seems to work.

Ultimately, I am trying to access the data ID so I can pass it to a child component using the event like this: (https://www.apexhours.com/events-in-lightning-web-components-lwc/)

export default class ParentComponent extends LightningElement {
handleChangeEvent(event){
    this.template.querySelector('c-child-Comp').changeMessage(event.target.value);
}

Here is my HTML

<template for:each={campaignMembers} for:item="member">
    <lightning-layout-item key={member.id} data-item={member} size="12" padding="horizontal-small" flexibility="auto" class="slds-card_boundary slds-m-bottom_small member-card" onclick={handleMemberClick}>
        <lightning-card icon-name={member.Icon} hoverable>
            <h4 slot="title">{member.FirstName} {member.LastName}</h4>
            <lightning-badge slot="actions" label={member.Status}></lightning-badge>
        </lightning-card>
    </lightning-layout-item>
</template>

Here is my JS

handleMemberClick(event) {

    console.log(event.target.dataset.member);
    console.log(event.currentTarget.dataset.member);

}

Answer 1

You made the property: data-item={member}, so to access it, it would be event.currentTarget.dataset.item. However, you should note that whatever you put into the attribute will have toString() called on it, so don't use the member itself, but instead, a unique value you can determine later, such as the record's Id (e.g. data-member-id={member.Id}), which you'd then find the appropriate record:

const member = this.campaignMembers.find((member) => member.Id === event.target.dataset.memberId)