Add private option to use npm 7

Author: WhiteAutumn

package.json

@@ -1,6 +1,6 @@
 {
   "name": "aws-lambda.js",
-  "version": "0.0.1",
+  "version": "0.0.2",
   "main": "dist/lambda.js",
   "repository": {
     "type": "git",

src/build.ts

@@ -38,11 +38,12 @@ const makeBuildDirectory = () => {
   return dir;
 };
 
-const makeDockerFile = (runtime: lambda.Runtime) => (`
+const makeDockerFile = (runtime: lambda.Runtime, useNpm7: boolean = false) => (`
 FROM ${runtime.bundlingImage.image}:latest
 
 COPY writeDependencies.js /lambda.js/writeDependencies.js
 
+${useNpm7 ? "RUN npm i -g npm@^7" : ""}
 RUN npm i -g typescript
 `);
 
@@ -70,6 +71,7 @@ export interface BuildPreparationOptions {
   entry: string;
   directory: string;
   inplace: boolean;
+  _bundleUsingNpm7?: boolean;
 }
 
 export interface BuildPreparationResult {
@@ -91,7 +93,7 @@ export interface BuildPreparationResult {
 export function prepareBuild(options: BuildPreparationOptions): BuildPreparationResult {
 
   const temporaryDirectory = makeBuildDirectory();
-  const dockerfile = makeDockerFile(options.runtime);
+  const dockerfile = makeDockerFile(options.runtime, options._bundleUsingNpm7);
 
   let cache;
   if (runtimeCache[options.directory] != null) {

src/lambda.ts

@@ -71,6 +71,8 @@ export interface FunctionProps extends lambda.FunctionOptions {
    * 
    */
   runtime?: lambda.Runtime;
+
+  _bundleUsingNpm7?: boolean;
 }
 
 export class Function extends lambda.Function {
@@ -90,7 +92,7 @@ export class Function extends lambda.Function {
       ...functionProps
     } = props;
 
-    const preparation = prepareBuild({ runtime, entry, directory, inplace });
+    const preparation = prepareBuild({ runtime, entry, directory, inplace, _bundleUsingNpm7: props._bundleUsingNpm7 });
 
     let codeOptions: s3_assets.AssetOptions = {
       exclude: makeLambdaExcludes(directory, preparation.info.sources, preparation.cache.paths)