11 comments

  • tantalor 7 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 2 hours 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

    • manojvivek 7 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 7 hours ago

        Offset is difference from a starting point or a previous position

        • jagged-chisel 5 hours ago

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

          • willrshansen 2 hours ago

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

            • eat_veggies an hour ago

              perhaps the delta between offsets

    • hanikesn 4 hours ago

      Delta Encoding is the common term

    • recursive 6 hours ago

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

    • paulddraper 2 hours 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 5 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