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How devtools map minified JS code back to your TypeScript source code

77 points by manojvivek - 13 comments
kayson [3 hidden]5 mins ago
I love it when things are displayed so nicely on mobile. This could've been a pain to read and get through but it was actually quite pleasant.
tantalor [3 hidden]5 mins ago
> Notice how the decoded values give relative positions, each value represents the difference from the previous position, not absolute coordinates. This is crucial: instead of encoding large column numbers like 27698 in minified files, source maps only store small deltas like +7 or +15, making the encoded strings much more compact.

Wouldn't "offset" be a more apt term?

manojvivek [3 hidden]5 mins ago
To me, “offset” sounds more like the distance from the start, whereas here the values are relative to the previous segment. Not a native english speaker, so I could be wrong.
tantalor [3 hidden]5 mins ago
Offset is difference from a starting point or a previous position
jagged-chisel [3 hidden]5 mins ago
“Offset” is not enough on its own. Offset from what? Start of file? Absolute offset. Previous offset? Relative offset.
willrshansen [3 hidden]5 mins ago
2nd order offset. The offset from the <offset from the start of the file>
eat_veggies [3 hidden]5 mins ago
perhaps the delta between offsets
hanikesn [3 hidden]5 mins ago
Delta Encoding is the common term
tracker1 [3 hidden]5 mins ago
Agreed... Delta Encoding, or even Delta Offset would work together.
accrual [3 hidden]5 mins ago
In this case I feel it's like six of one and a half-dozen of the other.

Delta definition 4: (mathematics, physics, engineering) The symbol Δ; A change in a quantity, likely from "d" for "difference"

Offset definition 7: The distance by which one thing is out of alignment with another.

Got these from Wiktionary:

* https://en.wiktionary.org/wiki/delta

* https://en.wiktionary.org/wiki/offset

recursive [3 hidden]5 mins ago
It sounds equally apt to my ear. I've used both words for this concept in the past.
paulddraper [3 hidden]5 mins ago
Delta and offset mean the same thing — the difference between two amounts.

Delta is perhaps slightly more obscure outside of a math setting. Perhaps.

zb3 [3 hidden]5 mins ago
Tangentially related, but last year I've made a tool to recover original sources from web apps which expose source maps (with the sourcesContent value present), including enumerating all lazily loaded chunks:

https://github.com/zb3/getfrontend