Implement remaining json host APIs (#487)

* Instantiate a new wasm string to convert JSON value to BigInt

* Implement remaining json host APIs

* Upgrade graph-ts and graph-cli in test example subgraph

* Handle null context for dataSource context host API

* Use JSONBig for parsing JSON strings

packages/graph-node/test/subgraph/example1/package.json

@@ -10,7 +10,7 @@
     "deploy-local": "graph deploy --node http://localhost:8020/ --ipfs http://localhost:5001 example1"
   },
   "dependencies": {
-    "@graphprotocol/graph-ts": "npm:@cerc-io/graph-ts@0.22.1-watcher-ts-0.1.0",
-    "@cerc-io/graph-cli": "0.22.4-watcher-ts-0.1.2"
+    "@graphprotocol/graph-ts": "npm:@cerc-io/graph-ts@0.27.0-watcher-ts-0.1.3",
+    "@cerc-io/graph-cli": "0.32.0-watcher-ts-0.1.3"
   }
 }

packages/graph-node/test/subgraph/example1/src/mapping.ts

@@ -577,13 +577,21 @@ export function testJsonFromBytes (): void {
   const numberValue = jsonData.toObject().get('numberValue')!;
   assert(numberValue.kind === JSONValueKind.NUMBER, 'JSON value is not a number');
 
-  // TODO: Debug json toI64 failing test case.
-  // const i64Value = numberValue.toI64();
-  // assert(i64Value == 123, 'values are not equal');
+  const i64Value = numberValue.toI64();
+  const expectedI64: i64 = 123;
+  assert(i64Value === expectedI64, 'i64 values are not equal');
 
-  // TODO: Debug json toBigInt failing test case.
-  // const bigIntValue = numberValue.toBigInt();
-  // assert(bigIntValue.toString() == '123', 'values are not equal');
+  const u64Value = numberValue.toU64();
+  const expectedU64: u64 = 123;
+  assert(u64Value === expectedU64, 'u64 values are not equal');
+
+  const f64Value = numberValue.toF64();
+  const expectedF64: f64 = 123;
+  assert(f64Value === expectedF64, 'f64 values are not equal');
+
+  const bigIntValue = numberValue.toBigInt();
+  const expectedBigInt = BigInt.fromString('123');
+  assert(bigIntValue.equals(expectedBigInt), 'BigInt values are not equal');
 }
 
 export function testJsonTryFromBytes (): void {

packages/graph-node/test/subgraph/example1/subgraph.yaml

@@ -1,4 +1,4 @@
-specVersion: 0.0.2
+specVersion: 0.0.4
 schema:
   file: ./schema.graphql
 dataSources: