Typorithm · hard
Step 1 of 4 · intro card
Adopt faster checking without confusing CLI compatibility with compiler-API compatibility.
As of this track’s review date, the pinned stable compiler is TypeScript 7.0.2. Its native implementation changes toolchain performance and integration details; it does not remove the need for explicit contracts, runtime validation or behavior tests. Published benchmark speedups are examples, not a guaranteed multiplier for every project.
Measure your own clean and incremental builds under controlled conditions. Record hardware, worker settings, compiler versions and project configuration. Compare the same workload rather than presenting a warm cached build against a cold baseline as proof of improvement.
TypeScript 7 is designed to align with TypeScript 6 checking behavior after the documented migration steps.
TypeScript 7 is designed to align with TypeScript 6 checking behavior after the documented migration steps. Its stable CLI can coexist with the TypeScript 6 compatibility package for tools that still embed the older programmatic API. Review each tool’s actual support instead of assuming a shared package name means compatibility.
Parallel checker and project-builder controls trade resources for throughput. Keep concurrency bounded on a small CI machine. A faster compiler is not permission to create unbounded type-level recursion or to increase a production server’s resource use.
typescript
function speedRatio(baseline:number,candidate:number):number{
if(!Number.isFinite(baseline)||!Number.isFinite(candidate)||baseline<=0||candidate<=0)throw new Error("Positive measured durations required");
return baseline/candidate;
}The rejected assignment shows that ordinary strict contracts still apply after the native implementation change.
The rejected assignment shows that ordinary strict contracts still apply after the native implementation change. A speed upgrade should not be used as an excuse to broaden a failing interface to any or discard negative regression fixtures.
Removed configuration options need actual replacements, including legacy resolution and baseUrl uses. The 7.0 stable compiler API story differs from the CLI; experimental entrypoints are not a promise of drop-in compatibility with the long-standing TypeScript JavaScript API.
typescript
function speedRatio(baseline:number,candidate:number):number{return baseline/candidate;}
// @ts-expect-error Durations are numeric measurements.
speedRatio("2 seconds",1);Build a tiny benchmark report function that calculates a ratio from two measured durations, rejecting nonpositive or nonfinite inputs.
Build a tiny benchmark report function that calculates a ratio from two measured durations, rejecting nonpositive or nonfinite inputs. This is a short data-quality exercise before comparing real builds. Keep the numbers supplied by the caller; do not invent benchmark claims.
Then run the same course fixtures through pinned 6.0.2 and 7.0.2 compilers. Optional extension: inspect project-reference build timing with bounded workers. The core goal is reproducible comparison, not maximizing concurrency on a shared machine.
Step 1: Validate measured durations. Step 2: Format only the observed ratio.
typescript
function ratioLabel(baseline:number,candidate:number):string{throw new Error("TODO: validate durations and format ratio");}The solution validates durations and divides baseline time by candidate time.
The solution validates durations and divides baseline time by candidate time. The result describes only those supplied measurements. A value of two means that measured baseline took twice as long; it does not establish a universal product claim or explain the cause.
Record compiler diagnostics, declaration changes and runtime behavior alongside timing. A migration is acceptable when its compatibility requirements are satisfied, not merely when one timing improves. Keep the prior working toolchain available for a reviewed rollback during adoption.
typescript
function ratioLabel(baseline:number,candidate:number):string{
if(!Number.isFinite(baseline)||!Number.isFinite(candidate)||baseline<=0||candidate<=0)throw new Error("Invalid measurement");
return `${(baseline/candidate).toFixed(2)}x for this measurement`;
}
// Acceptance checks
if(ratioLabel(2,1)!=="2.00x for this measurement")throw new Error("label");for(const x of [0,-1,NaN,Infinity]){let bad=false;try{ratioLabel(2,x)}catch{bad=true}if(!bad)throw new Error("measurement");}In interviews, distinguish native CLI adoption from programmatic compiler integration.
In interviews, distinguish native CLI adoption from programmatic compiler integration. Explain why benchmark methodology matters and how you would bound workers in CI. Mention experimental APIs as experimental rather than teaching them as stable replacements.
The next lesson is explicitly optional: TypeScript 7.1 beta. Its examples are isolated from stable grading and require a pinned preview compiler and a runtime or bundler that supports the proposed feature.
Optional stretch — after the core task works: Measure a bounded project-reference build.
Adopt faster checking without confusing CLI compatibility with compiler-API compatibility.