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Graph/b501d786-e788-4669-9f75-d96191ab5146

Domainunvalidated

Map vs Object

b501d786-e788-4669-9f75-d96191ab5146

Map vs Object

Node Details

Public graph metadata

Updated5/1/2026

PageRank0.0000

Effectiveness0.000

Connections

8 linked nodes

PERTAIN_TOProblem

you won't get a false positive if the name matches something in the prototype — When using objects, you have to use a method like `hasOwnProperty()` to distinguish properties of the object from properties inherited from the prototype. Tension: there's no conflict between element names used by the application and names provided from the language. Outcome: When using objects, you have to use a method like `hasOwnProperty()` to distinguish properties of the object from properties inherited from the prototype.

PERTAIN_TOSolution

When a key/value structure is needed, `Map` should be preferred to `Object`. Tension: there's no conflict between element names used by the application and names provided from the language. Outcome: Use a method like `hasOwnProperty()` to distinguish properties of the object from properties inherited from the prototype.

PERTAIN_TOProblem

const oldSet = Map.prototype.set; Map.prototype.set = function(key, value) { — malicious code. Tension: affects all instances present and future. Outcome: Your data is now stolen.

PERTAIN_TOSolution

Tension: so a bad NPM module that recently got updated, doesn't end up making your app compromised.

PERTAIN_TOProblem

In React Router v6, the user needs access to the current matched route's `id` (from `RouteObject`) to determine permissions, but `useLocation` and `useParams` do not provide it.

PERTAIN_TOSolution

Use the `useMatches` hook to get the array of matched routes (each includes `id`), then select the current match (e.g., by matching `pathname`) and read `match.id` to build the permission checks.

PERTAIN_TOProblem

java.lang.IllegalStateException: Duplicate key a (attempted merging values 1 and 1) — I'm trying to convert a list of objects to a `Map` using Java Streams. Tension: I expected it to just create a map with unique keys, but I forgot that my list has duplicates.

PERTAIN_TOSolution

You can use `Collectors.collectingAndThen`, but then you need to keep a list of the grouped values so you can access the nail index later — Collectors.collectingAndThen. Tension: you need to keep a list of the grouped values so you can access the nail index later.

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