javascript i wydajność - czy to się spina?
TRANSCRIPT
JAVASCRIPT I WYDAJNOŚĆ TO SIĘ SPINA?
AGENDA 01 Wprowadzenie 02 Restrykcje są cool 03 Po co się powtarzać? 04 Jeśli, a co jeśli nie? 05 Za dużo gadam 06 Przesuń to, przesuń tamto 07 TL;DR
01WPROWADZENIE
GLOBAL DIGITAL AGENCY1,900+ EMPLOYEES
ATLANTABEIJINGBOGOTÁBOSTONCAPE TOWNCHICAGO
GUANGZHOUJAKARTAJOHANNESBURGKALAMAZOOKANSAS CITYKRAKOW
LONDONMILANMUMBAINEW YORKSÃO PAULOSEATTLE
SHANGHAISINGAPORESYDNEYTOKYOWARSAWWHITE SALMON
PO CO TA PREZENTACJA
PRZYKŁADOWY KOD - ODWROTNA NOTACJA POLSKAfor (let i = 0; i < 10000; i++) { let stack = []; let str = '12 2 3 4 * 10 5 / + * +'; str = str.split(" "); let output = []; let currentOp = []; let num = 0; let string; for (let i in str) { num = parseInt(str[i]); if (isNaN(num)) { string = num.toString(); stack.push(str[i]); if (str.length > 0) { if (isNaN(str[i])) { output.push(stack.pop()); currentOp = []; for (let i = 0; i < 3; i++) { currentOp.push(output.pop()); this.popped = currentOp.reverse(); let x = currentOp[0]; let y = currentOp[2]; this.result = 0; if (currentOp[1] === "*") { result = x * y } else if (currentOp[1] === "/") { result = x / y } else if (currentOp[1] === "-") { result = x - y } else if (currentOp[1] === "+") { result = x + y } else if (currentOp[1] === "^") { result = Math.pow(x, y) } } output.push(result); } } } else { output.push(num); } } }
PRZYKŁADOWY KOD - ODWROTNA NOTACJA POLSKAfor (let i = 0; i < 10000; i++) { let stack = []; let str = '12 2 3 4 * 10 5 / + * +'; str = str.split(" "); let output = []; let currentOp = []; let num = 0; let string; for (let i in str) { num = parseInt(str[i]); if (isNaN(num)) { string = num.toString(); stack.push(str[i]); if (str.length > 0) { if (isNaN(str[i])) { output.push(stack.pop()); currentOp = []; for (let i = 0; i < 3; i++) { currentOp.push(output.pop()); this.popped = currentOp.reverse(); let x = currentOp[0]; let y = currentOp[2]; this.result = 0; if (currentOp[1] === "*") { result = x * y } else if (currentOp[1] === "/") { result = x / y } else if (currentOp[1] === "-") { result = x - y } else if (currentOp[1] === "+") { result = x + y } else if (currentOp[1] === "^") { result = Math.pow(x, y) } } output.push(result); } } } else { output.push(num); } } }
(2+3)*5
2 3 + 5 *
w odwrotnej notacji polskiej
PRZYKŁADOWY KOD - ODWROTNA NOTACJA POLSKAfor (let i = 0; i < 10000; i++) { let stack = []; let str = '12 2 3 4 * 10 5 / + * +'; str = str.split(" "); let output = []; let currentOp = []; let num = 0; let string; for (let i in str) { num = parseInt(str[i]); if (isNaN(num)) { string = num.toString(); stack.push(str[i]); if (str.length > 0) { if (isNaN(str[i])) { output.push(stack.pop()); currentOp = []; for (let i = 0; i < 3; i++) { currentOp.push(output.pop()); this.popped = currentOp.reverse(); let x = currentOp[0]; let y = currentOp[2]; this.result = 0; if (currentOp[1] === "*") { result = x * y } else if (currentOp[1] === "/") { result = x / y } else if (currentOp[1] === "-") { result = x - y } else if (currentOp[1] === "+") { result = x + y } else if (currentOp[1] === "^") { result = Math.pow(x, y) } } output.push(result); } } } else { output.push(num); } } }
(2+3)*5
2 3 + 5 *
w odwrotnej notacji polskiej
75 ms
~13fps
CO MOŻNA Z TYM ZROBIĆ?
02RESTRYKCJE SĄ COOL
ODWROTNA NOTACJA POLSKAfor (let i = 0; i < 10000; i++) { let stack = []; let str = '12 2 3 4 * 10 5 / + * +'; str = str.split(" "); let output = []; let currentOp = []; let num = 0; let string; for (let i in str) { num = parseInt(str[i]); if (isNaN(num)) { string = num.toString(); stack.push(str[i]); if (str.length > 0) { if (isNaN(str[i])) { output.push(stack.pop()); currentOp = []; for (let i = 0; i < 3; i++) { currentOp.push(output.pop()); this.popped = currentOp.reverse(); let x = currentOp[0]; let y = currentOp[2]; this.result = 0; if (currentOp[1] === "*") { result = x * y } else if (currentOp[1] === "/") { result = x / y } else if (currentOp[1] === "-") { result = x - y } else if (currentOp[1] === "+") { result = x + y } else if (currentOp[1] === "^") { result = Math.pow(x, y) } } output.push(result); } } } else { output.push(num); } } }
for (let i = 0; i < 10000; i++) { let stack = []; let str = '12 2 3 4 * 10 5 / + * +'; str = str.split(" "); let output = []; let currentOp = []; let num = 0; let string; for (let i in str) { num = parseInt(str[i]); if (isNaN(num)) { string = num.toString(); stack.push(str[i]); if (str.length > 0) { if (isNaN(str[i])) { output.push(stack.pop()); currentOp = []; for (let i = 0; i < 3; i++) { currentOp.push(output.pop()); this.popped = currentOp.reverse(); let x = currentOp[0]; let y = currentOp[2]; this.result = 0; if (currentOp[1] === "*") { result = x * y } else if (currentOp[1] === "/") { result = x / y } else if (currentOp[1] === "-") { result = x - y } else if (currentOp[1] === "+") { result = x + y } else if (currentOp[1] === "^") { result = Math.pow(x, y) } } output.push(result); } } } else { output.push(num); } } }
STRICT MODE
’use strict’;
for (let i = 0; i < 10000; i++) { let stack = []; let str = '12 2 3 4 * 10 5 / + * +'; str = str.split(" "); let output = []; let currentOp = []; let num = 0; let string; for (let i in str) { num = parseInt(str[i]); if (isNaN(num)) { string = num.toString(); stack.push(str[i]); if (str.length > 0) { if (isNaN(str[i])) { output.push(stack.pop()); currentOp = []; for (let i = 0; i < 3; i++) { currentOp.push(output.pop()); this.popped = currentOp.reverse(); let x = currentOp[0]; let y = currentOp[2]; this.result = 0; if (currentOp[1] === "*") { result = x * y } else if (currentOp[1] === "/") { result = x / y } else if (currentOp[1] === "-") { result = x - y } else if (currentOp[1] === "+") { result = x + y } else if (currentOp[1] === "^") { result = Math.pow(x, y) } } output.push(result); } } } else { output.push(num); } } }
STRICT MODE’use strict’;
03PO CO SIĘ POWTARZAĆ
’use strict’; for (let i = 0; i < 10000; i++) { let stack = []; let str = '12 2 3 4 * 10 5 / + * +'; str = str.split(" "); let output = []; let currentOp = []; let num = 0; let string; for (let i in str) { num = parseInt(str[i]); if (isNaN(num)) { string = num.toString(); stack.push(str[i]); if (str.length > 0) { if (isNaN(str[i])) { output.push(stack.pop()); currentOp = []; for (let i = 0; i < 3; i++) { currentOp.push(output.pop()); this.popped = currentOp.reverse(); let x = currentOp[0]; let y = currentOp[2]; this.result = 0; if (currentOp[1] === "*") { result = x * y } else if (currentOp[1] === "/") { result = x / y } else if (currentOp[1] === "-") { result = x - y } else if (currentOp[1] === "+") { result = x + y } else if (currentOp[1] === "^") { result = Math.pow(x, y) } } output.push(result); } } } else { output.push(num); } } }
ODWROTNA NOTACJA POLSKA
’use strict’; for (let i = 0; i < 10000; i++) { let stack = []; let str = '12 2 3 4 * 10 5 / + * +'; str = str.split(" "); let output = []; let currentOp = []; let num = 0; let string; for (let i in str) { num = parseInt(str[i]); if (isNaN(num)) { string = num.toString(); stack.push(str[i]); if (str.length > 0) { if (isNaN(str[i])) { output.push(stack.pop()); currentOp = []; for (let i = 0; i < 3; i++) { currentOp.push(output.pop()); this.popped = currentOp.reverse(); let x = currentOp[0]; let y = currentOp[2]; this.result = 0; if (currentOp[1] === "*") { result = x * y } else if (currentOp[1] === "/") { result = x / y } else if (currentOp[1] === "-") { result = x - y } else if (currentOp[1] === "+") { result = x + y } else if (currentOp[1] === "^") { result = Math.pow(x, y) } } output.push(result); } } } else { output.push(num); } } }
ODWROTNA NOTACJA POLSKA
REFACTORING ❤
’use strict’; for (let i = 0; i < 10000; i++) { let numArray = []; let input = '2 7 + 3 / 14 3 - 4 * + 2 /'; let toBeInterpeted = input.split(' ');
let isOperator = (val) => { if (val == '*' || val == '/' || val == '^' || val == '+' || val == '-') { return true; } return false; }
let performOperation = (symbol, val2, val1) => { switch(symbol) { case '*': return val1 * val2; case '/': return val1 / val2; case '+': return +val1 + +val2; case '-': return +val1 - +val2; case '^': return Math.pow(val1, val2); } }
for(let i = 0; i < toBeInterpeted.length; i++) { let num = toBeInterpeted[i]; let isOperatorSymbol = isOperator(num); if (isOperatorSymbol) { let value2 = numArray.pop(); let value1 = numArray.pop(); numArray.push(performOperation(num, value1, value2)); } else { numArray.push(num); } } }
DELEGACJA ZADAŃ DO DEDYKOWANYCH FUNKCJI
’use strict’; for (let i = 0; i < 10000; i++) { let numArray = []; let input = '2 7 + 3 / 14 3 - 4 * + 2 /'; let toBeInterpeted = input.split(' ');
let isOperator = (val) => { if (val == '*' || val == '/' || val == '^' || val == '+' || val == '-') { return true; } return false; }
let performOperation = (symbol, val2, val1) => { switch(symbol) { case '*': return val1 * val2; case '/': return val1 / val2; case '+': return +val1 + +val2; case '-': return +val1 - +val2; case '^': return Math.pow(val1, val2); } }
for(let i = 0; i < toBeInterpeted.length; i++) { let num = toBeInterpeted[i]; let isOperatorSymbol = isOperator(num); if (isOperatorSymbol) { let value2 = numArray.pop(); let value1 = numArray.pop(); numArray.push(performOperation(num, value1, value2)); } else { numArray.push(num); } } }
DELEGACJA ZADAŃ DO DEDYKOWANYCH FUNKCJI
DELEGACJA ZADAŃ DO DEDYKOWANYCH FUNKCJI - PORÓWNANIE
13.72 ops/s 41.59 ops/s
04JEŚLI, A CO JEŚLI NIE?
WYŻSZOŚĆ IF/ELSE
let performOperation = (symbol, val2, val1) => { switch(symbol) { case '*': return val1 * val2; case '/': return val1 / val2; case '+': return +val1 + +val2; case '-': return +val1 - +val2; case '^': return Math.pow(val1, val2); } }
let isOperator = (val) => { if (val == '*' || val == '/' || val == '^' || val == '+' || val == '-') { return true; } return false; }
let numArray = []; let input = '2 7 + 3 / 14 3 - 4 * + 2 /'; let toBeInterpeted = input.split(' ');
’use strict’; for (let i = 0; i < 10000; i++) {
for(let i = 0; i < toBeInterpeted.length; i++) { let num = toBeInterpeted[i]; let isOperatorSymbol = isOperator(num); if (isOperatorSymbol) { let value2 = numArray.pop(); let value1 = numArray.pop(); numArray.push(performOperation(num, value1, value2)); } else { numArray.push(num); } } }
WYŻSZOŚĆ IF/ELSE
let performOperation = (symbol, val2, val1) => { switch(symbol) { case '*': return val1 * val2; case '/': return val1 / val2; case '+': return +val1 + +val2; case '-': return +val1 - +val2; case '^': return Math.pow(val1, val2); } }
let isOperator = (val) => { if (val == '*' || val == '/' || val == '^' || val == '+' || val == '-') { return true; } return false; }
let numArray = []; let input = '2 7 + 3 / 14 3 - 4 * + 2 /'; let toBeInterpeted = input.split(' ');
’use strict’; for (let i = 0; i < 10000; i++) {
for(let i = 0; i < toBeInterpeted.length; i++) { let num = toBeInterpeted[i]; let isOperatorSymbol = isOperator(num); if (isOperatorSymbol) { let value2 = numArray.pop(); let value1 = numArray.pop(); numArray.push(performOperation(num, value1, value2)); } else { numArray.push(num); } } }
var x = true;var y = false;switch(true) {
case (x || y)://…
}
WYŻSZOŚĆ IF/ELSE
let performOperation = (symbol, val2, val1) => { switch(symbol) { case '*': return val1 * val2; case '/': return val1 / val2; case '+': return +val1 + +val2; case '-': return +val1 - +val2; case '^': return Math.pow(val1, val2); } }
let isOperator = (val) => { if (val == '*' || val == '/' || val == '^' || val == '+' || val == '-') { return true; } return false; }
let numArray = []; let input = '2 7 + 3 / 14 3 - 4 * + 2 /'; let toBeInterpeted = input.split(' ');
’use strict’; for (let i = 0; i < 10000; i++) {
for(let i = 0; i < toBeInterpeted.length; i++) { let num = toBeInterpeted[i]; let isOperatorSymbol = isOperator(num); if (isOperatorSymbol) { let value2 = numArray.pop(); let value1 = numArray.pop(); numArray.push(performOperation(num, value1, value2)); } else { numArray.push(num); } } }
var x = true;var y = false;switch(true) {
case (x || y)://…
}
WYŻSZOŚĆ IF/ELSE
let performOperation = (symbol, val2, val1) => { switch(symbol) { case '*': return val1 * val2; case '/': return val1 / val2; case '+': return +val1 + +val2; case '-': return +val1 - +val2; case '^': return Math.pow(val1, val2); } }
let isOperator = (val) => { if (val == '*' || val == '/' || val == '^' || val == '+' || val == '-') { return true; } return false; }
let numArray = []; let input = '2 7 + 3 / 14 3 - 4 * + 2 /'; let toBeInterpeted = input.split(' ');
’use strict’; for (let i = 0; i < 10000; i++) {
for(let i = 0; i < toBeInterpeted.length; i++) { let num = toBeInterpeted[i]; let isOperatorSymbol = isOperator(num); if (isOperatorSymbol) { let value2 = numArray.pop(); let value1 = numArray.pop(); numArray.push(performOperation(num, value1, value2)); } else { numArray.push(num); } } }
WYŻSZOŚĆ IF/ELSE
let isOperator = (val) => { if (val == '*' || val == '/' || val == '^' || val == '+' || val == '-') { return true; } return false; }
let numArray = []; let input = '2 7 + 3 / 14 3 - 4 * + 2 /'; let toBeInterpeted = input.split(' ');
’use strict’; for (let i = 0; i < 10000; i++) {
for(let i = 0; i < toBeInterpeted.length; i++) { let num = toBeInterpeted[i]; let isOperatorSymbol = isOperator(num); if (isOperatorSymbol) { let value2 = numArray.pop(); let value1 = numArray.pop(); numArray.push(performOperation(num, value1, value2)); } else { numArray.push(num); } } }
WYŻSZOŚĆ IF/ELSE
let isOperator = (val) => { if (val == '*' || val == '/' || val == '^' || val == '+' || val == '-') { return true; } return false; }
let numArray = []; let input = '2 7 + 3 / 14 3 - 4 * + 2 /'; let toBeInterpeted = input.split(' ');
’use strict’; for (let i = 0; i < 10000; i++) {
for(let i = 0; i < toBeInterpeted.length; i++) { let num = toBeInterpeted[i]; let isOperatorSymbol = isOperator(num); if (isOperatorSymbol) { let value2 = numArray.pop(); let value1 = numArray.pop(); numArray.push(performOperation(num, value1, value2)); } else { numArray.push(num); } } }
let performOperation = (symbol, val2, val1) => {if (symbol == '*') { return val1*val2; }else if (symbol == '/') { return val1/val2; }else if (symbol == '+') { return +val1 + +val2; }else if (symbol == '-') { return +val1 - +val2; }else if (symbol == '^') { return Math.pow(val1, val2); }
}
05ZA DUŻO GADAM
OGRANICZAMY ILOŚĆ ZMIENNYCH
let isOperator = (val) => { if (val == '*' || val == '/' || val == '^' || val == '+' || val == '-') { return true; } return false; }
let numArray = []; let input = '2 7 + 3 / 14 3 - 4 * + 2 /'; let toBeInterpeted = input.split(' ');
’use strict’; for (let i = 0; i < 10000; i++) {
} else {
} } }
if (symbol == '*') { return val1*val2; } else if (symbol == '/') { return val1/val2; } else if (symbol == '+') { return +val1 + +val2; } else if (symbol == '-') { return +val1 - +val2; } else if (symbol == '^') { return Math.pow(val1, val2); } }
for(let i = 0; i < toBeInterpeted.length; i++) { let num = toBeInterpeted[i]; let isOperatorSymbol = isOperator(num);
if (isOperatorSymbol) {
let performOperation = (symbol,
let value2 = numArray.pop(); let value1 = numArray.pop(); numArray.push(performOperation(num,
numArray.push(
val2, val1) => {
value1, value2));
num);
OGRANICZAMY ILOŚĆ ZMIENNYCH
let isOperator = (val) => { if (val == '*' || val == '/' || val == '^' || val == '+' || val == '-') { return true; } return false; }
let numArray = []; let input = '2 7 + 3 / 14 3 - 4 * + 2 /'; let toBeInterpeted = input.split(' ');
’use strict’; for (let i = 0; i < 10000; i++) {
} else {
} } }
if (symbol == '*') { return val1*val2; } else if (symbol == '/') { return val1/val2; } else if (symbol == '+') { return +val1 + +val2; } else if (symbol == '-') { return +val1 - +val2; } else if (symbol == '^') { return Math.pow(val1, val2); } }
for(let i = 0; i < toBeInterpeted.length; i++) {
if (isOperatorSymbol) {
let performOperation = (symbol,
let value2 = numArray.pop(); let value1 = numArray.pop(); numArray.push(performOperation(num,
numArray.push(
val2, val1) => {
value1, value2));
num);
OGRANICZAMY ILOŚĆ ZMIENNYCH
let isOperator = (val) => { if (val == '*' || val == '/' || val == '^' || val == '+' || val == '-') { return true; } return false; }
let numArray = []; let input = '2 7 + 3 / 14 3 - 4 * + 2 /'; let toBeInterpeted = input.split(' ');
’use strict’; for (let i = 0; i < 10000; i++) {
} else {
} } }
if (symbol == '*') { return val1*val2; } else if (symbol == '/') { return val1/val2; } else if (symbol == '+') { return +val1 + +val2; } else if (symbol == '-') { return +val1 - +val2; } else if (symbol == '^') { return Math.pow(val1, val2); } }
for(let i = 0; i < toBeInterpeted.length; i++) {
let performOperation = (symbol,
let value2 = numArray.pop(); let value1 = numArray.pop(); numArray.push(performOperation(num,
numArray.push(
if (isOperator(toBeInterpreted[i])) {
val2, val1) => {
value1, value2));
num);
OGRANICZAMY ILOŚĆ ZMIENNYCH
let isOperator = (val) => { if (val == '*' || val == '/' || val == '^' || val == '+' || val == '-') { return true; } return false; }
let numArray = []; let input = '2 7 + 3 / 14 3 - 4 * + 2 /'; let toBeInterpeted = input.split(' ');
’use strict’; for (let i = 0; i < 10000; i++) {
} else {
} } }
if (symbol == '*') { return val1*val2; } else if (symbol == '/') { return val1/val2; } else if (symbol == '+') { return +val1 + +val2; } else if (symbol == '-') { return +val1 - +val2; } else if (symbol == '^') { return Math.pow(val1, val2); } }
for(let i = 0; i < toBeInterpeted.length; i++) {
let performOperation = (symbol,
let value2 = numArray.pop(); let value1 = numArray.pop(); numArray.push(performOperation(num,
numArray.push(
if (isOperator(toBeInterpreted[i])) {
val1, val2) => {
value1, value2));
num);
OGRANICZAMY ILOŚĆ ZMIENNYCH
let isOperator = (val) => { if (val == '*' || val == '/' || val == '^' || val == '+' || val == '-') { return true; } return false; }
let numArray = []; let input = '2 7 + 3 / 14 3 - 4 * + 2 /'; let toBeInterpeted = input.split(' ');
’use strict’; for (let i = 0; i < 10000; i++) {
} else {
} } }
if (symbol == '*') { return val1*val2; } else if (symbol == '/') { return val1/val2; } else if (symbol == '+') { return +val1 + +val2; } else if (symbol == '-') { return +val1 - +val2; } else if (symbol == '^') { return Math.pow(val1, val2); } }
for(let i = 0; i < toBeInterpeted.length; i++) {
let performOperation = (symbol,
numArray.push(performOperation(num,
numArray.push(
if (isOperator(toBeInterpreted[i])) {
val1, val2) => {
value1, value2));
num);
OGRANICZAMY ILOŚĆ ZMIENNYCH
let isOperator = (val) => { if (val == '*' || val == '/' || val == '^' || val == '+' || val == '-') { return true; } return false; }
let numArray = []; let input = '2 7 + 3 / 14 3 - 4 * + 2 /'; let toBeInterpeted = input.split(' ');
’use strict’; for (let i = 0; i < 10000; i++) {
} else {
} } }
if (symbol == '*') { return val1*val2; } else if (symbol == '/') { return val1/val2; } else if (symbol == '+') { return +val1 + +val2; } else if (symbol == '-') { return +val1 - +val2; } else if (symbol == '^') { return Math.pow(val1, val2); } }
for(let i = 0; i < toBeInterpeted.length; i++) {
let performOperation = (symbol,
numArray.push(performOperation(num,
numArray.push(
if (isOperator(toBeInterpreted[i])) {
val1, val2) => {
numArray.pop(), numArray.pop()));
num);
OGRANICZAMY ILOŚĆ ZMIENNYCH
let isOperator = (val) => { if (val == '*' || val == '/' || val == '^' || val == '+' || val == '-') { return true; } return false; }
let numArray = []; let input = '2 7 + 3 / 14 3 - 4 * + 2 /'; let toBeInterpeted = input.split(' ');
’use strict’; for (let i = 0; i < 10000; i++) {
} else {
} } }
if (symbol == '*') { return val1*val2; } else if (symbol == '/') { return val1/val2; } else if (symbol == '+') { return +val1 + +val2; } else if (symbol == '-') { return +val1 - +val2; } else if (symbol == '^') { return Math.pow(val1, val2); } }
for(let i = 0; i < toBeInterpeted.length; i++) {
let performOperation = (symbol,
numArray.push(performOperation(num,
numArray.push(
if (isOperator(toBeInterpreted[i])) {
val1, val2) => {
numArray.pop(), numArray.pop()));
num);
OGRANICZAMY ILOŚĆ ZMIENNYCH
let isOperator = (val) => { if (val == '*' || val == '/' || val == '^' || val == '+' || val == '-') { return true; } return false; }
let numArray = []; let input = '2 7 + 3 / 14 3 - 4 * + 2 /'; let toBeInterpeted = input.split(' ');
’use strict’; for (let i = 0; i < 10000; i++) {
} else {
} } }
if (symbol == '*') { return val1*val2; } else if (symbol == '/') { return val1/val2; } else if (symbol == '+') { return +val1 + +val2; } else if (symbol == '-') { return +val1 - +val2; } else if (symbol == '^') { return Math.pow(val1, val2); } }
for(let i = 0; i < toBeInterpeted.length; i++) {
let performOperation = (symbol,
numArray.push(performOperation(num,
numArray.push(
if (isOperator(toBeInterpreted[i])) {
val1, val2) => {
numArray.pop(), numArray.pop()));
toBeInterpreted[i]);
OGRANICZAMY ILOŚĆ ZMIENNYCH
let isOperator = (val) => { if (val == '*' || val == '/' || val == '^' || val == '+' || val == '-') { return true; } return false; }
let numArray = []; let input = '2 7 + 3 / 14 3 - 4 * + 2 /'; let toBeInterpeted = input.split(' ');
’use strict’; for (let i = 0; i < 10000; i++) {
} else {
} } }
if (symbol == '*') { return val1*val2; } else if (symbol == '/') { return val1/val2; } else if (symbol == '+') { return +val1 + +val2; } else if (symbol == '-') { return +val1 - +val2; } else if (symbol == '^') { return Math.pow(val1, val2); } }
for(let i = 0; i < toBeInterpeted.length; i++) {
let performOperation = (symbol,
numArray.push(performOperation(num,
numArray.push(
if (isOperator(toBeInterpreted[i])) {
val1, val2) => {
numArray.pop(), numArray.pop()));
toBeInterpreted[i]);
OGRANICZAMY ILOŚĆ ZMIENNYCH - PORÓWNANIE
41.11 ops/s 200 ops/s
06PRZESUŃ TO, PRZESUŃ TAMTO
WYRZUCAMY STAŁE Z PĘTLI OBLICZENIOWEJ
isOperator = (val) => { if (val == '*' || val == '/' || val == '^' || val == '+' || val == '-') { return true; } return false; }
input = '2 7 + 3 / 14 3 - 4 * + 2 /'; toBeInterpeted = input.split(' ');
for (let i = 0; i < 10000; i++) { let numArray = [];
for(let i = 0; i < toBeInterpeted.length; i++) { if (isOperator(toBeInterpreted[i])) { numArray.push(performOperation(num, numArray.pop(), numArray.pop())); } else { numArray.push(toBeInterpreted[i]); } } }
performOperation = (symbol, val1, val2) => { if (symbol == '*') { return val1*val2; } else if (symbol == '/') { return val1/val2; } else if (symbol == '+') { return +val1 + +val2; } else if (symbol == '-') { return +val1 - +val2; } else if (symbol == '^') { return Math.pow(val1, val2); } }
let let
let
let
’use strict’;
WYRZUCAMY STAŁE Z PĘTLI OBLICZENIOWEJ
isOperator = (val) => { if (val == '*' || val == '/' || val == '^' || val == '+' || val == '-') { return true; } return false; }
input = '2 7 + 3 / 14 3 - 4 * + 2 /'; toBeInterpeted = input.split(' ');
for (let i = 0; i < 10000; i++) { let numArray = []; for(let i = 0; i < toBeInterpeted.length; i++) { if (isOperator(toBeInterpreted[i])) { numArray.push(performOperation(num, numArray.pop(), numArray.pop())); } else { numArray.push(toBeInterpreted[i]); } } }
performOperation = (symbol, val1, val2) => { if (symbol == '*') { return val1*val2; } else if (symbol == '/') { return val1/val2; } else if (symbol == '+') { return +val1 + +val2; } else if (symbol == '-') { return +val1 - +val2; } else if (symbol == '^') { return Math.pow(val1, val2); } }
letlet
let
let
’use strict’;
WYRZUCAMY STAŁE Z PĘTLI OBLICZENIOWEJ
isOperator = (val) => { if (val == '*' || val == '/' || val == '^' || val == '+' || val == '-') { return true; } return false; }
input = '2 7 + 3 / 14 3 - 4 * + 2 /'; toBeInterpeted = input.split(' ');
for (let i = 0; i < 10000; i++) { let numArray = []; for(let i = 0; i < toBeInterpeted.length; i++) { if (isOperator(toBeInterpreted[i])) { numArray.push(performOperation(num, numArray.pop(), numArray.pop())); } else { numArray.push(toBeInterpreted[i]); } } }
performOperation = (symbol, val1, val2) => { if (symbol == '*') { return val1*val2; } else if (symbol == '/') { return val1/val2; } else if (symbol == '+') { return +val1 + +val2; } else if (symbol == '-') { return +val1 - +val2; } else if (symbol == '^') { return Math.pow(val1, val2); } }
constconst
const
const
’use strict’;
WYRZUCAMY STAŁE Z PĘTLI OBLICZENIOWEJ - PORÓWNANIE
204 ops/s 279 ops/s
~75 ms
PODSUMOWANIE - ILE TERAZ TRWA CAŁA OPERACJA?
PODSUMOWANIE - ILE TERAZ TRWA CAŁA OPERACJA?
~3.5 ms(przyspieszenie o ~2050%)
'USE STRICT';
•kompilator nie musi się „domyślać”
•mniejsza szansa na głupi błąd
•niewielki skok wydajności
DELEGACJA ZADAŃ DO DEDYKOWANYCH FUNKCJI
•czystszy kod
•znaczny skok wydajności
IF/ELSE
•mikrooptymalizacja - do poświęcenia w celu zwiększenia czytelności kodu
•niewielki skok wydajności
OGRANICZ LICZBĘ ZMIENNYCH
•potrafi zmniejszyć czytelność kodu
•bardzo duży skok wydajności
PRZENIEŚ STAŁE Z PĘTLI OBLICZENIOWEJ
•zwiększa „reużywalność” kodu
•duży skok wydajności
TL;DR
LINKI
•https://mythbusters.js.org/
DZIĘKUJĘMichał Kostrzyński Frontend Developer [email protected] linkedin.com/in/michalkostrzynski
Zawartość niniejszej prezentacji, a w szczególności koncepcje i sposób prezentacji treści, stanowią własność intelektualną VML Poland, chronioną prawem zgodnie z ustawą z dnia 4 lutego 1994 r. o ochronie praw autorskich i praw pokrewnych. Wykorzystanie całości lub części niniejszego utworu w jakichkolwiek celach wymaga pisemnej zgody właściciela. Niniejsza oferta zachowuje ważność przez okres 3 miesięcy od daty otrzymania.
http://frontowo.pl
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