Handle large JSON payloads

packages/hardhat-core/package.json

@@ -120,6 +120,7 @@
     "glob": "^7.1.3",
     "immutable": "^4.0.0-rc.12",
     "io-ts": "1.10.4",
+    "json-stream-stringify": "^2.0.4",
     "lodash": "^4.17.11",
     "merkle-patricia-tree": "^4.2.2",
     "mnemonist": "^0.38.0",

packages/hardhat-core/src/internal/artifacts.ts

@@ -30,6 +30,7 @@ import { HardhatError } from "./core/errors";
 import { ERRORS } from "./core/errors-list";
 import { glob, globSync } from "./util/glob";
 import { createNonCryptographicHashBasedIdentifier } from "./util/hash";
+import { writeJson } from "./util/write-json";
 
 const log = debug("hardhat:core:artifacts");
 
@@ -130,7 +131,7 @@ export class Artifacts implements IArtifacts {
     await fsExtra.ensureDir(path.dirname(artifactPath));
 
     // write artifact
-    await fsExtra.writeJSON(artifactPath, artifact, {
+    await writeJson(artifactPath, artifact, {
       spaces: 2,
     });
 
@@ -142,7 +143,7 @@ export class Artifacts implements IArtifacts {
     const debugFilePath = this._getDebugFilePath(artifactPath);
     const debugFile = this._createDebugFile(artifactPath, pathToBuildInfo);
 
-    await fsExtra.writeJSON(debugFilePath, debugFile, {
+    await writeJson(debugFilePath, debugFile, {
       spaces: 2,
     });
   }
@@ -171,7 +172,8 @@ export class Artifacts implements IArtifacts {
     );
 
     const buildInfoPath = path.join(buildInfoDir, `${buildInfoName}.json`);
-    await fsExtra.writeJson(buildInfoPath, buildInfo, { spaces: 2 });
+
+    await writeJson(buildInfoPath, buildInfo, { spaces: 2 });
 
     return buildInfoPath;
   }

packages/hardhat-core/src/internal/util/write-json.ts

@@ -0,0 +1,36 @@
+import { createWriteStream } from 'fs';
+import JsonStreamStringify from 'json-stream-stringify';
+
+export interface Options {
+    encoding?: string;
+    flag?: string;
+    mode?: number;
+    replacer?: any;
+    spaces?: number | string;
+}
+
+export async function writeJson(file: string, object: object, options: Options) {
+    const { replacer, spaces, encoding, flag, mode } = options;
+    const jsonStream = new JsonStreamStringify(object, replacer, spaces);
+
+    const fsOptions = {
+        flags: flag,
+        encoding, mode
+    };
+    const f = createWriteStream(file, fsOptions);
+
+    jsonStream.once('error', () => console.log('Error in json-string-stream'));
+    jsonStream.pipe(f);
+
+    return new Promise((resolve, reject) => {
+        f.on('finish', () => {
+            f.close(err => {
+                if (err) {
+                    reject(err);
+                } else {
+                    resolve(file);
+                }
+            });
+        });
+    });
+}