FIX 4.2
The FIX 4.2 dictionary as shipped in @boarteam/fix-dict-fix42. Messages announce it in BeginString (tag 8) as FIX.4.2.
What it contains
No component blocks
FIX 4.2 predates component blocks: its dictionary declares only the standard header and trailer, and inlines every other field group directly into each message. A FIX 4.2 message body is therefore much flatter than the equivalent FIX 4.4 one, even where the fields are identical.
How it differs
Against FIX 4.4: FIX 4.2 carries 35 fields that FIX 4.4 does not define. The other way round, FIX 4.4 has 542 fields, 47 message types and 103 components with no FIX 4.2 counterpart.
Against FIX 5.0 SP2: FIX 4.2 carries 35 fields that FIX 5.0 SP2 does not define. The other way round, FIX 5.0 SP2 has 1082 fields, 69 message types and 174 components with no FIX 4.2 counterpart.
35 fields appear in FIX 4.2 and in neither of the other two versions covered here — the most used:
These are presence counts only. For the renamed fields, changed datatypes and enum differences, see FIX 4.4 vs FIX 4.2 — every entity page also shows per-version presence and requiredness side by side.
Decode FIX 4.2 in TypeScript
import { createFixEngine } from "@boarteam/fix";import { dictionary } from "@boarteam/fix-dict-fix42";const fix = createFixEngine(dictionary);const { message, issues } = fix.parse(raw);message.beginString; // "FIX.4.2"issues; // FixIssue[] — never an exceptionDecode this in your own code
The same engine that produced the decoded example above is an Apache-2.0 npm package with zero runtime dependencies. It runs in Node and in the browser, and parse() returns problems as data instead of throwing.
npm i @boarteam/fix @boarteam/fix-dict-fix42