provide array data length in SArray

.gitignore

@@ -2,4 +2,9 @@
 # Mac desktop service store files
 .DS_Store
 
+# node.js
 /node_modules/
+pnpm-lock.yaml
+
+# IDE
+.idea/

es/index.d.ts

@@ -1,5 +1,6 @@
 export interface SArray<T> {
     (): T[];
+    length: number;
     concat(...others: (() => T | T[])[]): SArray<T>;
     every(pred: (v: T) => boolean): () => boolean;
     filter(pred: (v: T) => boolean): SArray<T>;
@@ -43,6 +44,7 @@ export declare function find<T>(seq: () => T[], pred: (v: T) => boolean): () =>
 export declare function includes<T>(seq: () => T[], o: T): () => boolean;
 export declare function sort<T>(seq: () => T[], fn?: (a: T, b: T) => number): () => T[];
 export declare function orderBy<T>(seq: () => T[], by: keyof T | ((v: T) => any)): () => T[];
+export declare function length<T>(seq: () => T[]): () => number;
 export declare function filter<T>(seq: () => T[], predicate: (v: T) => boolean): () => T[];
 export declare function concat<T>(seq: () => T[], ...others: (() => T | T[])[]): () => T[];
 export declare function reduce<T, U>(seq: () => T[], fn: (r: U, t: T, i: number, s: T[]) => U, seed: U | (() => U)): () => U;

es/index.js

@@ -117,6 +117,12 @@ export function lift(seq) {
     _seq.reverse = chainReverse;
     _seq.slice = chainSlice;
     _seq.some = chainSome;
+    Object.defineProperty(_seq, 'length', {
+        // get: length(_seq)
+        get: function length() {
+            return _seq().length;
+        }
+    });
     // non-ES5 transformers
     _seq.mapS = chainMapS;
     _seq.mapSample = chainMapSample;
@@ -420,6 +426,12 @@ export function orderBy(seq, by) {
 function chainOrderBy(by) {
     return lift(orderBy(this, by));
 }
+export function length(seq) {
+    return S(function length() {
+        var s = seq();
+        return s.length;
+    });
+}
 export function filter(seq, predicate) {
     return S(function filter() {
         var s = seq(), result = [], i, v;

index.js

@@ -124,6 +124,12 @@
         _seq.reverse = chainReverse;
         _seq.slice = chainSlice;
         _seq.some = chainSome;
+        Object.defineProperty(_seq, 'length', {
+            // get: length(_seq)
+            get: function length() {
+                return _seq().length;
+            }
+        });
         // non-ES5 transformers
         _seq.mapS = chainMapS;
         _seq.mapSample = chainMapSample;
@@ -427,6 +433,12 @@
     function chainOrderBy(by) {
         return lift(orderBy(this, by));
     }
+    function length(seq) {
+        return S(function length() {
+            var s = seq();
+            return s.length;
+        });
+    }
     function filter(seq, predicate) {
         return S(function filter() {
             var s = seq(), result = [], i, v;
@@ -544,6 +556,7 @@
     exports.includes = includes;
     exports.sort = sort;
     exports.orderBy = orderBy;
+    exports.length = length;
     exports.filter = filter;
     exports.concat = concat;
     exports.reduce = reduce;

index.ts

@@ -3,6 +3,7 @@ import S from "s-js";
 
 export interface SArray<T> {
     () : T[];
+    length: number;
 
     concat(...others : (() => T | T[])[]) : SArray<T>;
     every(pred : (v : T) => boolean) : () => boolean;
@@ -197,6 +198,12 @@ export function lift<T>(seq : () => T[]) {
     _seq.reverse     = chainReverse;
     _seq.slice       = chainSlice;
     _seq.some        = chainSome;
+    Object.defineProperty(_seq, 'length', {
+        // get: length(_seq)
+        get: function length() {
+            return _seq().length;
+        }
+    });
 
     // non-ES5 transformers
     _seq.mapS        = chainMapS;
@@ -615,6 +622,14 @@ function chainOrderBy<T>(this : () => T[], by : keyof T | ((v : T) => any)) {
     return lift(orderBy(this, by));
 }
 
+export function length<T>(seq : () => T[]) {
+    return S(function length() {
+        var s = seq();
+
+        return s.length;
+    });
+}
+
 export function filter<T>(seq : () => T[], predicate : (v : T) => boolean) {
     return S(function filter() {
         var s = seq(),

package.json

@@ -9,16 +9,21 @@
     "s-js": "^0.4.9"
   },
   "devDependencies": {
+    "chai": "^4.2.0",
     "jasmine": "^3.1.0",
     "karma": "^2.0.5",
     "karma-chrome-launcher": "^2.2.0",
     "karma-jasmine": "^1.1.2",
+    "mocha": "^7.1.0",
     "rollup": "^0.63.4",
+    "s-js": "^0.4.9",
     "typescript": "^2.9.2"
   },
   "scripts": {
     "build": "tsc && rollup -c",
-    "test": "karma start"
+    "test": "npm run karma || npm run mocha",
+    "karma": "karma start",
+    "mocha": "mocha spec/SArray-mocha.spec.js"
   },
   "keywords": [
     "S.js",