fix(trace): Support tracing of object-parameters with circular references

Closes #75

Author: christopherthielen

src/params/paramTypes.ts

@@ -286,15 +286,15 @@ function initDefaultTypes() {
       encode: (val: any) => val && 1 || 0,
       decode: (val: string) => parseInt(val, 10) !== 0,
       is: is(Boolean),
-      pattern: /0|1/
+      pattern: /0|1/,
     }),
 
     date: makeDefaultType({
       encode: function(val: any) {
         return !this.is(val) ? undefined : [
           val.getFullYear(),
           ('0' + (val.getMonth() + 1)).slice(-2),
-          ('0' + val.getDate()).slice(-2)
+          ('0' + val.getDate()).slice(-2),
         ].join("-");
       },
       decode: function(val: string) {
@@ -305,18 +305,18 @@ function initDefaultTypes() {
       is: (val: any) => val instanceof Date && !isNaN(val.valueOf()),
       equals(l: any, r: any) {
         return ['getFullYear', 'getMonth', 'getDate']
-            .reduce((acc, fn) => acc && l[fn]() === r[fn](), true)
+            .reduce((acc, fn) => acc && l[fn]() === r[fn](), true);
       },
       pattern: /[0-9]{4}-(?:0[1-9]|1[0-2])-(?:0[1-9]|[1-2][0-9]|3[0-1])/,
-      capture: /([0-9]{4})-(0[1-9]|1[0-2])-(0[1-9]|[1-2][0-9]|3[0-1])/
+      capture: /([0-9]{4})-(0[1-9]|1[0-2])-(0[1-9]|[1-2][0-9]|3[0-1])/,
     }),
 
     json: makeDefaultType({
       encode: toJson,
       decode: fromJson,
       is: is(Object),
       equals: equals,
-      pattern: /[^/]*/
+      pattern: /[^/]*/,
     }),
 
     // does not encode/decode
@@ -326,8 +326,7 @@ function initDefaultTypes() {
       is: () => true,
       equals: equals,
     }),
-  })
-
+  });
 }
 
 initDefaultTypes();

src/state/targetState.ts

@@ -7,8 +7,8 @@ import { StateDeclaration, StateOrName, TargetStateDef } from "./interface";
 import { ParamsOrArray } from "../params/interface";
 import { TransitionOptions } from "../transition/interface";
 import { StateObject } from "./stateObject";
-import { toJson } from "../common/common";
 import { isString } from "../common/predicates";
+import { stringify } from '../common/strings';
 
 /**
  * Encapsulate the target (destination) state/params/options of a [[Transition]].
@@ -119,7 +119,7 @@ export class TargetState {
   }
 
   toString() {
-    return `'${this.name()}'${toJson(this.params())}`;
+    return `'${this.name()}'${stringify(this.params())}`;
   }
 
   /** Returns true if the object has a state property that might be a state or state name */

src/transition/transition.ts

@@ -5,9 +5,8 @@
 /** for typedoc */
 import { trace } from '../common/trace';
 import { services } from '../common/coreservices';
-import {
-  map, find, extend, mergeR, tail, omit, toJson, arrayTuples, unnestR, identity, anyTrueR,
-} from '../common/common';
+import { stringify } from '../common/strings';
+import { map, find, extend, mergeR, tail, omit, arrayTuples, unnestR, identity, anyTrueR } from '../common/common';
 import {isObject, isUndefined} from '../common/predicates';
 import { prop, propEq, val, not, is } from '../common/hof';
 import { StateDeclaration, StateOrName } from '../state/interface';
@@ -753,10 +752,10 @@ export class Transition implements IHookRegistry {
     // (X) means the to state is invalid.
     let id = this.$id,
         from = isObject(fromStateOrName) ? fromStateOrName.name : fromStateOrName,
-        fromParams = toJson(avoidEmptyHash(this._treeChanges.from.map(prop('paramValues')).reduce(mergeR, {}))),
+        fromParams = stringify(avoidEmptyHash(this._treeChanges.from.map(prop('paramValues')).reduce(mergeR, {}))),
         toValid = this.valid() ? "" : "(X) ",
         to = isObject(toStateOrName) ? toStateOrName.name : toStateOrName,
-        toParams = toJson(avoidEmptyHash(this.params()));
+        toParams = stringify(avoidEmptyHash(this.params()));
 
     return `Transition#${id}( '${from}'${fromParams} -> ${toValid}'${to}'${toParams} )`;
   }