createSourceMap() — tailwindcss Function Reference

Architecture documentation for the createSourceMap() function in source-map.ts from the tailwindcss codebase.

Function typescript OxideEngine Scanner calls 3 called by 1

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OxideEngine→ Scanner→ createSourceMap() — tailwindcss Function Reference

Dependency Diagram

graph TD
  ce95eae1_6998_4776_5146_d52bb0aefb63["createSourceMap()"]
  94f6a4ae_3b1f_8e71_a096_1f7d17efc49a["source-map.ts"]
  ce95eae1_6998_4776_5146_d52bb0aefb63 -->|defined in| 94f6a4ae_3b1f_8e71_a096_1f7d17efc49a
  9c33d37f_aea4_85fa_1eb9_f13429950630["compile()"]
  9c33d37f_aea4_85fa_1eb9_f13429950630 -->|calls| ce95eae1_6998_4776_5146_d52bb0aefb63
  0204f9b9_80aa_c3e8_eb61_22170d608d65["createLineTable()"]
  ce95eae1_6998_4776_5146_d52bb0aefb63 -->|calls| 0204f9b9_80aa_c3e8_eb61_22170d608d65
  ed78da58_8727_ad98_120c_61f35cea357a["walk()"]
  ce95eae1_6998_4776_5146_d52bb0aefb63 -->|calls| ed78da58_8727_ad98_120c_61f35cea357a
  5bcf4886_1230_a8ff_7302_a26cc5a9a525["get()"]
  ce95eae1_6998_4776_5146_d52bb0aefb63 -->|calls| 5bcf4886_1230_a8ff_7302_a26cc5a9a525
  style ce95eae1_6998_4776_5146_d52bb0aefb63 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

packages/tailwindcss/src/source-maps/source-map.ts lines 76–163

export function createSourceMap({ ast }: { ast: AstNode[] }) {
  // Compute line tables for both the original and generated source lazily so we
  // don't have to do it during parsing or printing.
  let lineTables = new DefaultMap<Source, LineTable>((src) => createLineTable(src.code))
  let sourceTable = new DefaultMap<Source, DecodedSource>((src) => ({
    url: src.file,
    content: src.code,
    ignore: false,
  }))

  // Convert each mapping to a set of positions
  let map: DecodedSourceMap = {
    file: null,
    sources: [],
    mappings: [],
  }

  // Get all the indexes from the mappings
  walk(ast, (node) => {
    if (!node.src || !node.dst) return

    let originalSource = sourceTable.get(node.src[0])
    if (!originalSource.content) return

    let originalTable = lineTables.get(node.src[0])
    let generatedTable = lineTables.get(node.dst[0])

    let originalSlice = originalSource.content.slice(node.src[1], node.src[2])

    // Source maps only encode single locations — not multi-line ranges
    // So to properly emulate this we'll scan the original text for multiple
    // lines and create mappings for each of those lines that point to the
    // destination node (whether it spans multiple lines or not)
    //
    // This is not 100% accurate if both the source and destination preserve
    // their newlines but this only happens in the case of custom properties
    //
    // This is _good enough_
    let offset = 0
    for (let line of originalSlice.split('\n')) {
      if (line.trim() !== '') {
        let originalStart = originalTable.find(node.src[1] + offset)
        let generatedStart = generatedTable.find(node.dst[1])

        map.mappings.push({
          name: null,
          originalPosition: {
            source: originalSource,
            ...originalStart,
          },
          generatedPosition: generatedStart,
        })
      }

      offset += line.length
      offset += 1
    }

    let originalEnd = originalTable.find(node.src[2])
    let generatedEnd = generatedTable.find(node.dst[2])

    map.mappings.push({
      name: null,
      originalPosition: {
        source: originalSource,
        ...originalEnd,
      },
      generatedPosition: generatedEnd,
    })
  })

  // Populate
  for (let source of lineTables.keys()) {
    map.sources.push(sourceTable.get(source))
  }

  // Sort the mappings in ascending order
  map.mappings.sort((a, b) => {
    return (
      a.generatedPosition.line - b.generatedPosition.line ||
      a.generatedPosition.column - b.generatedPosition.column ||