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

44 pointsposted 5 hours ago
by manojvivek

10 Comments

tantalor

5 hours 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?

accrual

27 minutes 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

hanikesn

2 hours ago

Delta Encoding is the common term

manojvivek

5 hours 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

5 hours ago

Offset is difference from a starting point or a previous position

jagged-chisel

3 hours ago

“Offset” is not enough on its own. Offset from what? Start of file? Absolute offset. Previous offset? Relative offset.

willrshansen

27 minutes ago

2nd order offset. The offset from the <offset from the start of the file>

paulddraper

19 minutes 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.

recursive

4 hours ago

It sounds equally apt to my ear. I've used both words for this concept in the past.

zb3

3 hours 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