TypeError: state.generator[node.type] is not a function

[Florentin Soubrand]

Motivation

I was trying to translate a JSON AST to JS code through 'json-to-ast' library and Astring but the error in the title occured.

Expected behavior

After importing generate like this :
const { generate } = require('astring')

Calling generate with an AST as parameter like this :
const code = generate(ast)
should not trigger an error

Actual behavior

Here is the complete error with "my_file.js" being the source code:
`/home/[...]/node_modules/astring/dist/astring.js:1209
state.generator[node.type](node, state);
^

TypeError: state.generator[node.type] is not a function
at generate (/home/[...]/node_modules/astring/dist/astring.js:1209:29)
at Object. (/home/[...]/my_file.js:977:14)
at Module._compile (node:internal/modules/cjs/loader:1241:14)
at Module._extensions..js (node:internal/modules/cjs/loader:1295:10)
at Module.load (node:internal/modules/cjs/loader:1091:32)
at Module._load (node:internal/modules/cjs/loader:938:12)
at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:83:12)
at node:internal/main/run_main_module:23:47

Node.js v20.6.0`

[David Bonnet]

Thanks for raising this @florentin-soubrand. The error is most likely due to a node type being unknown to the Estree specification, and thus to Astring as well (my hunch is that json-to-ast outputs object nodes with "Object" as its type instead of "ObjectExpression").

An easy fix would be to normalize the AST output by json-to-ast to an Estree compatible one.