sourcemap生成格式错误，导致还原失败

// 还原脚本
const fs = require('fs')
const SourceMap = require('source-map')


async function originalPositionFor(line, column) {
   const sourceMapFilePath = "/Users/smithdeng/Desktop/testd/mpvue_demo_to_reappear_sourcemap_bug/reappear_sourcemap_bug/dist/wx/app.js.map"
   const sourceMapConsumer = await new SourceMap.SourceMapConsumer
                            (JSON.parse(fs.readFileSync(sourceMapFilePath, 'utf8')))
   const res = sourceMapConsumer.originalPositionFor({
      line,
      column,
   })
   console.log(res)
}

originalPositionFor(3,506)