Merge 852ca57 into 2aa5dc8

discoveryjs · Aug 6, 2019 · c72ab11 · c72ab11
2 parents 2aa5dc8 + 852ca57
commit c72ab11
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Showing 7 changed files with 388 additions and 5 deletions.
diff --git a/.gitignore b/.gitignore
@@ -1,3 +1,4 @@
+/.idea/
 /.vscode/
 /.cache/
 /.nyc_output/

diff --git a/src/buildin.js b/src/buildin.js
@@ -2,7 +2,8 @@ const {
     addToSet,
     getPropertyValue,
     isPlainObject,
-    isRegExp
+    isRegExp,
+    isArrayLike
 } = require('./utils');
 
 module.exports = Object.freeze({
@@ -117,6 +118,42 @@ module.exports = Object.freeze({
 
         return value !== undefined ? fn(value) : value;
     },
+    slice: function(value, from, to, step) {
+        if (!isArrayLike(value)) {
+            return value;
+        }
+
+        if (step && step !== 1) {
+            const result = [];
+            const reverse = step < 0;
+
+            step *= Math.sign(step);
+
+            if (from < 0) {
+                from = value.length + from;
+            }
+
+            if (to < 0) {
+                to = value.length + to;
+            }
+
+            for (let i = from; i < to; i += step) {
+                result.push(value[i]);
+            }
+
+            if (reverse) {
+                result.reverse();
+            }
+
+            return result;
+        }
+
+        if (typeof value.slice === 'function') {
+            return value.slice(from, to);
+        }
+
+        return Array.prototype.slice.call(value, from, to);
+    },
     recursive: function(value, getter) {
         const result = new Set();
 

diff --git a/src/methods.js b/src/methods.js
@@ -1,7 +1,8 @@
 const buildin = require('./buildin');
 const {
     addToSet,
-    isPlainObject
+    isPlainObject,
+    isArrayLike
 } = require('./utils');
 
 function noop() {}
@@ -128,6 +129,13 @@ module.exports = Object.freeze({
 
         return current.slice().reverse();
     },
+    slice: function(current, from, to) {
+        if (!isArrayLike(current)) {
+            return current;
+        }
+
+        return current.slice(from, to);
+    },
     group: function(current, keyGetter, valueGetter) {
         if (typeof keyGetter !== 'function') {
             keyGetter = noop;

diff --git a/src/parser.js b/src/parser.js
@@ -255,7 +255,16 @@ const grammar = {
             ['. SYMBOL ( arguments )', code`method.$2(/*@2*/current, $4)`],
             ['.. SYMBOL', code`fn.recursive(/*@2*/current, "$2")`],
             ['..( block )', code`fn.recursive(current, current => { $2 })`],
-            ['.[ block ]', code`fn.filter(current, current => { $2 })`]
+            ['.[ block ]', code`fn.filter(current, current => { $2 })`],
+            ['[ e : e ]', code`fn.slice(current, $2, $4, 1)`],
+            ['[ e : e : e ]', code`fn.slice(current, $2, $4, $6)`],
+            ['[ : e ]', code`fn.slice(current, 0, $3, 1)`],
+            ['[ : e : e ]', code`fn.slice(current, 0, $3, $5)`],
+            ['[ e : ]', code`fn.slice(current, $2, current.length, 1)`],
+            ['[ e : : e ]', code`fn.slice(current, $2, current.length, $5)`],
+            ['[ : ]', code`fn.slice(current, 0, current.length, 1)`],
+            ['[ : : e ]', code`fn.slice(current, 0, current.length, $4)`],
+            ['[ : : ]', code`fn.slice(current, 0, current.length, 1)`]
         ],
 
         relativePath: [
@@ -266,7 +275,16 @@ const grammar = {
             ['query .. SYMBOL', code`fn.recursive(/*@3*/$1, "$3")`],
             ['query ..( block )', code`fn.recursive($1, current => { $3 })`],
             ['query .[ block ]', code`fn.filter($1, current => { $3 })`],
-            ['query [ e ]', code`fn.map($1, $3)`]
+            ['query [ e ]', code`fn.map($1, $3)`],
+            ['query [ e : e ]', code`fn.slice($1, $3, $5, 1)`],
+            ['query [ e : e : e ]', code`fn.slice($1, $3, $5, $7)`],
+            ['query [ : e ]', code`fn.slice($1, 0, $4, 1)`],
+            ['query [ : e : e ]', code`fn.slice($1, 0, $4, $6)`],
+            ['query [ e : ]', code`fn.slice($1, $3, $1.length, 1)`],
+            ['query [ e : : e ]', code`fn.slice($1, $2, $1.length, $6)`],
+            ['query [ : ]', code`fn.slice($1, 0, $1.length, 1)`],
+            ['query [ : : e ]', code`fn.slice($1, 0, $1.length, $5)`],
+            ['query [ : : ]', code`fn.slice($1, 0, $1.length, 1)`]
         ],
 
         arguments: [

diff --git a/src/utils.js b/src/utils.js
@@ -24,9 +24,16 @@ function isRegExp(value) {
     return toString.call(value) === '[object RegExp]';
 }
 
+function isArrayLike(value) {
+    return value &&
+        hasOwnProperty.call(value, 0) &&
+        hasOwnProperty.call(value, 'length');
+}
+
 module.exports = {
     addToSet,
     getPropertyValue,
     isPlainObject,
-    isRegExp
+    isRegExp,
+    isArrayLike
 };
diff --git a/test/methods-buildin.js b/test/methods-buildin.js
@@ -73,6 +73,42 @@ describe('buildin methods', () => {
         });
     });
 
+    describe('slice()', () => {
+        it('arrays', () => {
+            assert.deepEqual(
+                query('filename.slice()')(data),
+                ['1.css', '2.js', '3.svg', '4.js', '5.js', '6.css', '7.css']
+            );
+
+            assert.deepEqual(
+                query('filename.slice(1)')(data),
+                ['2.js', '3.svg', '4.js', '5.js', '6.css', '7.css']
+            );
+
+            assert.deepEqual(
+                query('filename.slice(1, 3)')(data),
+                ['2.js', '3.svg']
+            );
+        });
+
+        it('string', () => {
+            assert.deepEqual(
+                query('filename.pick().slice()')(data),
+                '1.css'
+            );
+
+            assert.deepEqual(
+                query('filename.pick().slice(1)')(data),
+                '.css'
+            );
+
+            assert.deepEqual(
+                query('filename.pick().slice(1, 2)')(data),
+                '.'
+            );
+        });
+    });
+
     describe('keys()', () => {
         it('basic', () => {
             assert.deepEqual(