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Diffstat (limited to 'node_modules/esm-import-transformer')
| -rw-r--r-- | node_modules/esm-import-transformer/README.md | 91 | ||||
| -rw-r--r-- | node_modules/esm-import-transformer/import-transformer.js | 232 | ||||
| -rw-r--r-- | node_modules/esm-import-transformer/package.json | 26 |
3 files changed, 349 insertions, 0 deletions
diff --git a/node_modules/esm-import-transformer/README.md b/node_modules/esm-import-transformer/README.md new file mode 100644 index 0000000..3b9a8bb --- /dev/null +++ b/node_modules/esm-import-transformer/README.md @@ -0,0 +1,91 @@ +# esm-import-transformer + +Can transform any ESM source code `import` URLs using an import maps object. This package works in ESM or CJS. + +```js +// Input source code: +import {html, css, LitElement} from "lit"; + +// Transform with an import map: +import {html, css, LitElement} from "https://cdn.jsdelivr.net/gh/lit/dist@2/core/lit-core.min.js"; + +// Or transform to a dynamic import: +const {html, css, LitElement} = await import("lit"); + +// Or transform to CommonJS require: +const {html, css, LitElement} = require("lit"); +``` + +## Usage + +```js +// ESM +import { ImportTransformer } from "esm-import-transformer"; + +// or CJS +const { ImportTransformer } = await import("esm-import-transformer"); +``` + +### Transform with an import map + +Pass in a source code string and an [import maps](https://github.com/WICG/import-maps) object. + +```js +let sourceCode = `import {html, css, LitElement} from "lit";`; +let it = new ImportTransformer(sourceCode); + +let importMap = { + imports: { + lit: "https://cdn.jsdelivr.net/gh/lit/dist@2/core/lit-core.min.js" + } +}; +let outputCode = it.transformWithImportMap(importMap); +// returns: `import {html, css, LitElement} from "https://cdn.jsdelivr.net/gh/lit/dist@2/core/lit-core.min.js";` +``` + +### Transform to dynamic `import()` + +```js +let sourceCode = `import {html, css, LitElement} from "lit";`; +let it = new ImportTransformer(sourceCode); + +let outputCode = it.transformToDynamicImport(); +// returns: `const {html, css, LitElement} = await import("lit");` +``` + +### Transform to `require()` + +_Added in v3.0.1_: This method does _not_ require that the downstream package is CommonJS, but remember that _running_ the resulting code will fail if you try to `require` an ESM package (in some JavaScript environments, e.g. Node < 20). + +```js +let sourceCode = `import {html, css, LitElement} from "lit";`; +let it = new ImportTransformer(sourceCode); + +let outputCode = it.transformToRequire(); +// returns: `const {html, css, LitElement} = require("lit");` +``` + +### Has imports? + +_Added in v3.0.2_ Returns true if the code has any top level `import`. + +```js +let sourceCode = `import {html, css, LitElement} from "lit";`; +let it = new ImportTransformer(sourceCode); +it.hasImports(); // true +``` + +```js +let sourceCode = `const {html, css, LitElement} = require("lit");`; +let it = new ImportTransformer(sourceCode); +it.hasImports(); // false +``` + + +## Installation + +Available on [npm](https://www.npmjs.com/package/esm-import-transformer) + +``` +npm install esm-import-transformer +``` diff --git a/node_modules/esm-import-transformer/import-transformer.js b/node_modules/esm-import-transformer/import-transformer.js new file mode 100644 index 0000000..4b09aa1 --- /dev/null +++ b/node_modules/esm-import-transformer/import-transformer.js @@ -0,0 +1,232 @@ +import { parse } from "acorn"; + +const COMMENT_START = "/* "; +const COMMENT_END = " */"; +const EXPORT_STR = "export "; + +export class ImportTransformer { + constructor(input, ast) { + this.parse(input, ast); + } + + parse(input, ast) { + if(!input) { + throw new Error("Missing input to ImportTransformer, received: " + input) + } + + this.originalSource = input; + + if(ast) { + this.ast = ast; + } else { + this.ast = parse(input, { + sourceType: "module", + ecmaVersion: "latest" + }); + } + + this.imports = new Set(); + this.exports = new Set(); + this.namedExports = new Set(); + } + + static commentNode(str, sourceNode, indexOffset = 0) { + let { start, end } = sourceNode; + let statement = str.slice(start + indexOffset, end + indexOffset); + return { + statement, + code: `${str.slice(0, start + indexOffset)}${COMMENT_START}${statement}${COMMENT_END}${str.slice(end + indexOffset)}`, + offset: COMMENT_START.length + COMMENT_END.length, + }; + } + + static commentExportDeclarationOnly(str, sourceNode, indexOffset = 0) { + let { start, end } = sourceNode; + let statement = str.slice(start + indexOffset, end + indexOffset); + + let functionDeclarationName = sourceNode.declaration?.id?.name; + let variableIdentifierNames = (sourceNode.declaration?.declarations || []).map(node => { + if(node.id.properties) { + return node.id.properties.map(node => node.key.name) + } else if(node.id.name) { + return node.id.name; + } + + throw new Error("Could not find variable identifier in declaration for: " + statement); + }).flat(); + + let reuseStatement; + // change `export const a = 1;` to `export { a };` for reuse + if(functionDeclarationName || variableIdentifierNames.length > 0) { + reuseStatement = `export { ${functionDeclarationName || variableIdentifierNames.join(", ") } };`; + } else { + throw new Error("Couldn’t find identifier name for: " + statement); + } + + // -1 there removes the double space between `export ` and ` */` + let commented = `${COMMENT_START}${EXPORT_STR.slice(0, -1)}${COMMENT_END}${statement.slice(EXPORT_STR.length)}` + return { + statement: reuseStatement, + namedExports: functionDeclarationName ? [functionDeclarationName] : variableIdentifierNames, + code: `${str.slice(0, start + indexOffset)}${commented}${str.slice(end + indexOffset)}`, + offset: COMMENT_START.length + COMMENT_END.length - 1, // -1 removes the double space between `export ` and ` */` + }; + } + + static transformImportSource(str, sourceNode, indexOffset = 0, importMap = {}) { + let { start, end, value } = sourceNode; + // Could be improved by https://www.npmjs.com/package/@import-maps/resolve + let resolved = importMap?.imports && importMap?.imports[value]; + if(resolved) { + return { + code: `${str.slice(0, start + 1 + indexOffset)}${resolved}${str.slice(end - 1 + indexOffset)}`, + offset: resolved.length - value.length, + }; + } + return { + code: str, + offset: 0 + }; + } + + static transformImportCode(prefix, str, node, specifiers, sourceNode, indexOffset = 0) { + let { start, end } = node; + let endOffset = end - sourceNode.end; + + start += indexOffset; + end += indexOffset; + + let { raw: rawSourceValue } = sourceNode; + let importDeclaration = str.slice(start, end); + + let specifierIndexes = []; + if(importDeclaration.startsWith("import * as ")) { + specifierIndexes[0] = "import * as ".length + start; + } else if(importDeclaration.startsWith("import ")) { + specifierIndexes[0] = "import ".length + start; + } else { + throw new Error(`Could not find \`import\` in import declaration: ${importDeclaration}`); + } + + specifierIndexes[1] = specifiers[specifiers.length - 1].end + indexOffset; + + // normalize away trailing } on import { a, b, c } specifiers + let split = str.slice(specifierIndexes[1]).split(" from "); + if(split.length > 0) { + specifierIndexes[1] += split[0].length; + } + + let newImportString = `const ${str.slice(specifierIndexes[0], specifierIndexes[1])} = ${prefix}(${rawSourceValue})`; + let returnedCode = str.slice(0, start) + newImportString + str.slice(end - endOffset); + + return { + code: returnedCode, + offset: returnedCode.length - str.length, + }; + } + + _transform(prefix) { + let input = this.originalSource; + let indexOffset = 0; + for(let node of this.ast.body) { + if(node.type === "ImportDeclaration") { + let ret = ImportTransformer.transformImportCode(prefix, input, node, node.specifiers, node.source, indexOffset) + input = ret.code; + indexOffset += ret.offset; + } + } + + return input; + } + + transformToDynamicImport() { + return this._transform("await import"); + } + + transformToRequire() { + return this._transform("require"); + } + + // alias for backwards compat + transform(...args) { + return this.transformWithImportMap(...args); + } + + transformRemoveImportExports() { + let input = this.originalSource; + let indexOffset = 0; + for(let node of this.ast.body) { + if(node.type === "ImportDeclaration") { + let ret = ImportTransformer.commentNode(input, node, indexOffset); + input = ret.code; + indexOffset += ret.offset; + this.imports.add(ret.statement); + } else if(node.type?.startsWith("Export")) { + let ret; + // comment out `export { name }` and `export default` + if(node.type === "ExportNamedDeclaration" && node.specifiers.length > 0 || node.type === "ExportDefaultDeclaration") { + ret = ImportTransformer.commentNode(input, node, indexOffset); + if(node.type === "ExportDefaultDeclaration") { + this.namedExports.add("default"); + } else { + for(let specifierNode of node.specifiers || []) { + if(specifierNode?.exported?.name) { + this.namedExports.add(specifierNode.exported.name); + } + } + } + } else { + // just comment out start `export ` from the beginning of `export const` or `export function` + ret = ImportTransformer.commentExportDeclarationOnly(input, node, indexOffset); + for(let name of ret.namedExports) { + this.namedExports.add(name); + } + } + + input = ret.code; + indexOffset += ret.offset; + this.exports.add(ret.statement); + } + } + + return input; + } + + getImportsAndExports() { + return { + imports: this.imports, + exports: this.exports, + namedExports: this.namedExports, + }; + } + + transformWithImportMap(importMap) { + if(!importMap) { + return this.originalSource; + } + + let input = this.originalSource; + let indexOffset = 0; + for(let node of this.ast.body) { + if(node.type === "ImportDeclaration") { + if(importMap?.imports) { + let ret = ImportTransformer.transformImportSource(input, node.source, indexOffset, importMap); + input = ret.code; + indexOffset += ret.offset; + } + } + } + + return input; + } + + hasImports() { + for(let node of this.ast.body) { + if(node.type === "ImportDeclaration") { + return true; + } + } + + return false; + } +} diff --git a/node_modules/esm-import-transformer/package.json b/node_modules/esm-import-transformer/package.json new file mode 100644 index 0000000..fa9c624 --- /dev/null +++ b/node_modules/esm-import-transformer/package.json @@ -0,0 +1,26 @@ +{ + "name": "esm-import-transformer", + "version": "3.0.5", + "description": "Perform transformations on ESM import syntax (using import maps or to a dynamic import).", + "type": "module", + "main": "./import-transformer.js", + "repository": { + "type": "git", + "url": "git+https://github.com/zachleat/esm-import-transformer.git" + }, + "author": { + "name": "Zach Leatherman", + "email": "zachleatherman@gmail.com", + "url": "https://zachleat.com/" + }, + "license": "MIT", + "scripts": { + "test": "npx ava" + }, + "dependencies": { + "acorn": "^8.15.0" + }, + "devDependencies": { + "ava": "^6.4.1" + } +} |