convert-source-map-simple

index.js

var sourceMap = require("source-map")

function convert(map) {
  var simpleMap = shallowCopy(map)

  // Prevent the source-map module from joining sources with the sourceRoot (if
  // any), so that we can find the indexes of in the `sources` property.
  delete simpleMap.sourceRoot

  simpleMap.mappings = {}
  new sourceMap.SourceMapConsumer(map).eachMapping(function(mapping) {
    var newMapping = []
    if (mapping.source != null) {
      newMapping.push(
        simpleMap.sources.indexOf(mapping.source),
        mapping.originalLine,
        mapping.originalColumn
      )
      if (mapping.name != null) {
        newMapping.push(simpleMap.names.indexOf(mapping.name))
      }
    }

    var line = simpleMap.mappings[mapping.generatedLine]
    if (!line) {
      line = simpleMap.mappings[mapping.generatedLine] = {}
    }
    line[mapping.generatedColumn] = newMapping
  })

  // Re-add the sourceRoot if needed.
  if ("sourceRoot" in map) {
    simpleMap.sourceRoot = map.sourceRoot
  }

  return simpleMap
}

function shallowCopy(obj) {
  var copy = {}
  Object.keys(obj).forEach(function(key) {
    copy[key] = obj[key]
  })
  return copy
}

module.exports = convert

package.json

{
  "name": "convert-source-map-simple",
  "version": "0.0.1",
  "dependencies": {
    "source-map": "~0.1.40"
  }
}