Added jsTruthy flag to constuctor in order to enable JS style truthiness evaluation

src/render/boolean.ts

@@ -1,6 +1,15 @@
-export function isTruthy (val: any): boolean {
-  return !isFalsy(val)
+import { Context } from '../context/context'
+
+export function isTruthy (val: any, ctx: Context): boolean {
+  if ((val === null) && ctx && ctx.opts && ctx.opts.jsTruthy ) return false;
+  return !isFalsy(val, ctx)
 }
-export function isFalsy (val: any): boolean {
-  return val === false || undefined === val || val === null
+
+export function isFalsy (val: any, ctx: Context): boolean {
+  if(ctx && ctx.opts && ctx.opts.jsTruthy) {
+    return val == false
+  }
+  else {
+    return val === false || undefined === val || val === null
+  }
 }

src/render/expression.ts

@@ -26,7 +26,7 @@ export class Expression {
       if (TypeGuards.isOperatorToken(token)) {
         const r = this.operands.pop()
         const l = this.operands.pop()
-        const result = evalOperatorToken(token, l, r)
+        const result = evalOperatorToken(token, l, r, ctx)
         this.operands.push(result)
       } else {
         this.operands.push(evalToken(token, ctx))
@@ -62,9 +62,9 @@ export function evalQuotedToken (token: QuotedToken) {
   return parseStringLiteral(token.getText())
 }
 
-function evalOperatorToken (token: OperatorToken, lhs: any, rhs: any) {
+function evalOperatorToken (token: OperatorToken, lhs: any, rhs: any, ctx: Context) {
   const impl = operatorImpls[token.operator]
-  return impl(lhs, rhs)
+  return impl(lhs, rhs, ctx)
 }
 
 function evalLiteralToken (token: LiteralToken) {

src/render/operator.ts

@@ -1,8 +1,10 @@
 import { isComparable } from '../drop/comparable'
+import { Context } from '../context/context'
 import { isFunction } from '../util/underscore'
 import { isTruthy } from '../render/boolean'
 
-export const operatorImpls: {[key: string]: (lhs: any, rhs: any) => boolean} = {
+
+export const operatorImpls: {[key: string]: (lhs: any, rhs: any, ctx: Context) => boolean} = {
   '==': (l: any, r: any) => {
     if (isComparable(l)) return l.equals(r)
     if (isComparable(r)) return r.equals(l)
@@ -36,6 +38,6 @@ export const operatorImpls: {[key: string]: (lhs: any, rhs: any) => boolean} = {
   'contains': (l: any, r: any) => {
     return l && isFunction(l.indexOf) ? l.indexOf(r) > -1 : false
   },
-  'and': (l: any, r: any) => isTruthy(l) && isTruthy(r),
-  'or': (l: any, r: any) => isTruthy(l) || isTruthy(r)
+  'and': (l: any, r: any, ctx: Context) => isTruthy(l, ctx) && isTruthy(r, ctx),
+  'or': (l: any, r: any, ctx: Context) => isTruthy(l, ctx) || isTruthy(r, ctx)
 }