export default class Approvals extends LightningElement {
    @track pendingApprovalHistories =[
        { Name : "Han Solo", CreatedDate : "test123" }
    ];
    actions = [
        { label: 'Make Decision', name: 'make_decision' },
    ];
   columns = [
        { label: 'Name', fieldName: 'name',  sortable: true },
        { label: 'Opportunity Owner', fieldName: 'opportunityOwnerName' },
        { label: 'Relationship Name', fieldName: 'accountName' },
        { label: 'Primary Approver', fieldName: 'ownerName' },
        { label: 'Created Date', fieldName: 'createdDate' },
        {
            type: 'action',
            typeAttributes: { rowActions: this.actions },
        },
    ];
    handleRowAction(event) {
        console.log(JSON.stringify("Hello!"));
        const actionName = event.detail.action.name;
        const row = event.detail.row;
        this.makeDecision(row);
    }
    makeDecision(row) {
        console.log(JSON.stringify("Hello2!"));
    }
}

<template>
<lightning-datatable key-field="id" hide-checkbox-column data={pendingApprovalHistories} columns={columns} onrowaction={handleRowAction}>
</lightning-datatable>
</template