Babel: Replacing ArrowFunctionExpression vs FunctionDeclaration in ExportDefaultDeclaration

问题:

Say I have the following code I want to transform:

export default () => {}; 

The following visitor code works:

export default function ({ types: t }) {   return {     visitor: {       ArrowFunctionExpression(path) {         if (!path.node.body.directives.some(d => d.value.value === 'inject')) return;         path.node.body.directives = path.node.body.directives.filter(d => d.value.value !== 'inject');         path.replaceWith(t.arrayExpression([path.node]));       }     }   }; } 

That results in the following output:

export default [() => {}]; 

Great! Now change the input:

export default function () {   'inject'; }; 

And the visitor:

export default function ({types: t}) {   return {     visitor: {       FunctionDeclaration(path) {         if (!path.node.body.directives.some(d => d.value.value === 'inject')) return;         path.node.body.directives = path.node.body.directives.filter(d => d.value.value !== 'inject');         path.replaceWith(t.arrayExpression([path.node]));       }     }   }; } 

That produces the following error:

TypeError: unknown: Property elements[0] of ArrayExpression expected node to be of a type ["null","Expression","SpreadElement"] but instead got "FunctionDeclaration"

Okay, so convert the FunctionDeclaration to a FunctionExpression:

export default function ({types: t}) {   return {     visitor: {       FunctionDeclaration(path) {         if (!path.node.body.directives.some(d => d.value.value === 'inject')) return;         path.node.body.directives = path.node.body.directives.filter(d => d.value.value !== 'inject');         path.replaceWith(           t.arrayExpression([             t.functionExpression(path.node.id, path.node.params, path.node.body, path.node.generator, path.node.async),           ])         );       }     }   }; } 

And I get the following error:

TypeError: unknown: Property declaration of ExportDefaultDeclaration expected node to be of a type ["FunctionDeclaration","ClassDeclaration","Expression"] but instead got "ExpressionStatement"

And that is where I'm lost. I'm creating an ArrayExpression just as I was with the default-exported arrow function. Why is it complaining about receiving an ExpressionStatement?

Note, the desired output is as such:

export default [function () { }]; 

文章来源: Babel: Replacing ArrowFunctionExpression vs FunctionDeclaration in ExportDefaultDeclaration