/
generate-import.ts
67 lines (57 loc) · 2.08 KB
/
generate-import.ts
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import type { ImportType } from 'src'
import type { Analyzed } from './analyze'
export interface ImportRecord {
node: AcornNode
importExpression?: string
importedName?: string
}
export function generateImport(analyzed: Analyzed, id: string, rules?: ImportType | ((id: string) => ImportType)) {
const imports: ImportRecord[] = []
let count = 0
for (const { node, dynamic } of analyzed.require) {
// Handled in `dynamic-require.ts`
if (dynamic === 'dynamic') continue
const impt: ImportRecord = { node }
const importName = `__CJS__import__${count++}__`
const requireIdNode = node.arguments[0]
let requireId: string
if (!requireIdNode) continue // Not value - require()
if (requireIdNode.type === 'Literal') {
requireId = requireIdNode.value
} else if (dynamic === 'Literal') {
requireId = requireIdNode.quasis[0].value.raw
}
if (!requireId!) {
const codeSnippets = analyzed.code.slice(node.start, node.end)
throw new Error(`The following require statement cannot be converted.
-> ${codeSnippets}
${'^'.repeat(codeSnippets.length)}`)
}
// This is probably less accurate but is much cheaper than a full AST parse.
let importType: ImportType = 'defaultFirst'
if (rules) {
if (typeof rules === 'string') {
importType = rules
}
if (typeof rules === 'function') {
importType = rules(id) || 'defaultFirst'
}
}
impt.importExpression = `import * as ${importName} from '${requireId}'`
switch (importType) {
case 'defaultFirst':
impt.importedName = `${importName}.default || ${importName}`
break
case 'namedFirst':
impt.importedName = `Object.keys(${importName}).join('') !== 'default' ? ${importName} : ${importName}.default`
break
case 'merge':
impt.importedName = `${importName}.default ? Object.assign(${importName}.default, ${importName}) : ${importName}`;
break
default:
throw new Error(`Unknown import type: ${importType} for ${id}`)
}
imports.push(impt)
}
return imports
}