36 lines
1.2 KiB
Markdown
36 lines
1.2 KiB
Markdown
importance: 5
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---
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# Create an extendable calculator
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Create a constructor function `Calculator` that creates "extendable" calculator objects.
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The task consists of two parts.
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1. First, implement the method `calculate(str)` that takes a string like `"1 + 2"` in the format "NUMBER operator NUMBER" (space-delimited) and returns the result. Should understand plus `+` and minus `-`.
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Usage example:
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```js
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let calc = new Calculator;
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alert( calc.calculate("3 + 7") ); // 10
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```
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2. Then add the method `addOperator(name, func)` that teaches the calculator a new operation. It takes the operator `name` and the two-argument function `func(a,b)` that implements it.
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For instance, let's add the multiplication `*`, division `/` and power `**`:
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```js
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let powerCalc = new Calculator;
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powerCalc.addMethod("*", (a, b) => a * b);
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powerCalc.addMethod("/", (a, b) => a / b);
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powerCalc.addMethod("**", (a, b) => a ** b);
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let result = powerCalc.calculate("2 ** 3");
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alert( result ); // 8
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```
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- No brackets or complex expressions in this task.
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- The numbers and the operator are delimited with exactly one space.
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- There may be error handling if you'd like to add it.
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