yup - How to conditionally validate at least one of n values are set?

var yup = require('yup') var invariant = require('invariant') var without = require("lodash.without") yup.addMethod(yup.object, 'atLeastOneRequired', function atLeastOneRequired(list, message) { invariant(list.every(field => this.fields[field]), 'All required fields should be defined before calling atLeastOneRequired'); return this.shape(list.reduce((acc, field) => ({ ...acc, [field]: this.fields[field].when(without(list, field), { is: (...values) => !values.some(item => item), then: this.fields[field].required(message), }), }), {}), list.reduce((acc, item, idx, all) => [...acc, ...all.slice(idx + 1).map(i => [item, i])], [])); }); var schema = yup.object().shape({ a: yup.string(), b: yup.string(), c: yup.string(), d: yup.string() }).atLeastOneRequired(['a', 'b', 'c', 'd']) await schema.validate({ a: '', b: '', c: '', d: '1' })