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@hrldcpr
Last active August 31, 2017 19:51
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ex-exampda
// We have some state like:
const state1 = {
data: { some: 'stuff' },
people: ['blah', 'blah', 'blah'],
memberships: [
{ id: 1, roles: [], other: 'stuff' },
{ id: 2, roles: ['client'], more: 'junk' }
]
};
// We want to be able to add a role to a particular membership (without mutation) (but without ramda):
const addRole = (id, role) => (obj) => {
const newMemberships = obj.memberships.map((membership) => {
if (membership.id == id) {
const newRoles = membership.roles.concat(role)
return Object.assign({}, membership, {roles: newRoles})
} else {
return membership
}
})
return Object.assign({}, obj, {memberships: newMemberships})
}
// For example:
addRole(2, 'admin')(state1)
// …returns a new object, in which `data`, `people`, and membership id 1 are all the exact same objects as before (not copies):
{
data: { some: 'stuff' },
people: ['blah', 'blah', 'blah'],
memberships: [
{ id: 1, roles: [], other: 'stuff' },
{ id: 2, roles: ['client', 'admin'], more: 'junk' }
]
}
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