currentCallback is not a function

[yuzhouu]

os: win10
node: v8.5.0
source-map: 0.7.2

the below function will run into error currentCallback is not a function

function mergeSourcemap(
  sourceMapConsumer_1,
  sourceMapConsumer_2
) {
    sourceMapConsumer_2.eachMapping((mappingItem) => {
    const { source, column, line } = sourceMapConsumer_1.originalPositionFor({
      column: m.originalColumn,
      line: m.originalLine,
    });
  });
}

error stack:

TypeError: currentCallback is not a function
    at mapping_callback (D:\Workspace\js\sourcemap-composer\node_modules\source-map\lib\wasm.js:64:13)
    at <WASM UNNAMED> (<WASM>[30]+196)
    at BasicSourceMapConsumer_eachMapping._wasm.withMappingCallback (D:\Workspace\js\sourcemap-composer\node_modules\source-map\lib\source-map-consumer.js:404:30)
    at Object.withMappingCallback (D:\Workspace\js\sourcemap-composer\node_modules\source-map\lib\wasm.js:95:11)
    at BasicSourceMapConsumer_eachMapping [as eachMapping] (D:\Workspace\js\sourcemap-composer\node_modules\source-map\lib\source-map-consumer.js:388:16)

I guess it is caused by I invoke originnalPositionFor method of consumer_1 in the eachMapping method of consumer_2.

and for your reference

• if I hoist the sourceMapConsumer_1.originalPositionFor from the eachMapping, this will work well
• the same code work well in the source-map@0.5.6

thank you for your glance

[mjomble]

I just ran into the same problem about 20 minutes after you created the issue :)

Temporary workaround that uses more memory:

const mappingItems = [];

sourceMapConsumer_2.eachMapping((mappingItem) => mappingItems.push(mappingItem));

// The consumer can be destroyed before the for loop 
sourceMapConsumer_2.destroy();

for (const mappingItem of mappingItems) {
  const { source, column, line } = sourceMapConsumer_1.originalPositionFor({
    column: mappingItem.originalColumn,
    line: mappingItem.originalLine,
  });
  ...
}

sourceMapConsumer_1.destroy();

[yuzhouu]

@mjomble yes I do the same thing to work around, as mentioned in reference 1, It dit work.

Wish mainteners have more gentler solution.

[fitzgen]

Thanks for filing an issue.

I think this is a dupe of #330 and #319 -- can you reproduce on master?

[yuzhouu]

@fitzgen great job, the master branch fix the issue, Looking forward to the release of the next version

[fitzgen]

Published 0.7.3