Throw error when exporting non-declaration #241
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| return this.parseStatement(true); | ||
| const statement = this.parseStatement(true); | ||
| if (!this.isDeclaration(statement)) { | ||
| this.unexpected(statement.start); |
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Since we know what the problem is here (an export that doesn't have a valid declaration or export clause) maybe we can use this.raise and hint to the user what the problem was?
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After discussing a bit with @hzoo, I changed it to an ahead of time check rather than checking the export statement post-parse. This actually changes the error message in some cases, so wanted to see what do you think.
If we want a more descriptive error message I could leave the original conditional and do the shouldParseExportDeclaration check (maybe now called isDeclaration?) inside that block, throwing a more descriptive error if isDeclaration returns false.
My only concern with the error message is that I'm not sure we can be sure of what the intention of the code is. If Babylon is trying to parse export typeof foo, can we surmise they intended to export a declaration? Or did you mean a more generic "Not a valid export" type of message? Let me know if I'm missing something!
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Or did you mean a more generic "Not a valid export" type of message
Yep! Just some message indicating that we know it's an export, it's just not a valid one.
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Hmmm, actually, going to explore checking token values ahead of time rather than the node type afterwards |
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Updated |
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Sorry, one last update - added return value flow type and moved the |
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Nice thanks |
Currently, Babylon will parse any export that starts with a keyword as a declaration. These changes will throw when the statement following the
exportkeyword is not a declaration.