How devtools map minified JS code back to your TypeScript source code
7 comments
·November 4, 2025tantalor
recursive
It sounds equally apt to my ear. I've used both words for this concept in the past.
manojvivek
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
Offset is difference from a starting point or a previous position
jagged-chisel
“Offset” is not enough on its own. Offset from what? Start of file? Absolute offset. Previous offset? Relative offset.
null
[deleted]
zb3
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:
> 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?