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Discussion on: Strongly Typed JSON in TypeScript

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Nick Taylor

The reason it’s a compiler option is because it can slow down the compiler for large data. You might be better off using a codegen tool to generate the types for that large JSON file.

Read big JSON files? #42761

Bug Report

🔎 Search Terms

"large json files"

Problem

None of the predefined sections are relevant here.

I'm trying to get types from a JSON file using resolveJsonModule. I'm using VS Code to do everything here. My JSON file is 4.9 MB and 200k lines. When I try to inspect the result of require('./big-file.json), it says {}. But it works great for another smaller file, albeit a bit slow.

Not sure if this is relevant or not, but it also fails for this big file in quicktype and works for the slightly smaller file. I assumed they're using TypeScript's parser/compiler under the hood, which would explain it. If they're not, then maybe it's a Node.js limitation that it's coming across.

To be clear, the require call itself works fine and returns a valid JSON object. So it might not be a Node.js memory limitation issue. But it might be one if TypeScript is more than doubling the memory by all its type analysis, or by duplicating substrings, etc.

Just some thoughts. I have no idea what's going on. All I know is that I was hoping VS Code would analyze my JSON files for me, but it's only working on some files.

Specifically this comment.