2learn

State Management

What it is

State management is the set of decisions about where an application’s data lives and who may change it. It is not the name of a library: a library may be involved, but the decisions come first. The questions are always the same — which component owns this value, who else needs to read it, how does a change reach everyone who displays it, and is this value ours to own at all or is it a copy of something the server already knows.

Why it matters

Front-end applications fail in a characteristic way when these questions go unanswered: the same fact is stored in three places and two of them are stale. A user edits their name in a dialog, the header still shows the old one, and the bug is filed against the header. The tooling can hide this for a while and then cannot fix it, because no single place knows the truth. Deciding the ownership model early — local where possible, shared deliberately, server data treated as a cache rather than as state — is what keeps that failure from happening at all.

In this track

  1. Local versus shared state (02-frontend/23-state-management/01-local-versus-shared-state) — starting with the smallest scope that works and lifting it only when a second consumer appears.
  2. Client and server state (02-frontend/23-state-management/02-client-and-server-state) — why data fetched from an API is a different problem from data the user is editing.

Prerequisites

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