我有以下代码:
<?php
$a = 1;
$b = 2;
echo "sum: " . $a + $b;
echo "sum: " . ($a + $b);
?>
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当我执行我的代码时,我得到:
2
sum: 3
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为什么它无法"sum:"在第一个回声中打印字符串?将附加括在括号中似乎没问题.
这种奇怪的行为是否记录在案?
试图运行Jest测试React代码的例子(来自https://github.com/facebook/jest/tree/master/examples/react),我收到以下错误:
> @ test /home/aizquier/jest/examples/react
> jest
Using Jest CLI v0.7.1
FAIL __tests__/CheckboxWithLabel-test.js
? Runtime Error
SyntaxError: /home/aizquier/jest/examples/react/__tests__/CheckboxWithLabel-test.js: Unexpected token (15:6)
npm ERR! Test failed. See above for more details.
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测试在文件CheckboxWithLabel-test.js的第15行失败:
jest.dontMock('../CheckboxWithLabel');
import React from 'react';
import ReactDOM from 'react-dom';
import TestUtils from 'react-addons-test-utils';
const CheckboxWithLabel = require('../CheckboxWithLabel');
describe('CheckboxWithLabel', function() {
it('changes the text after click', function() {
// Render a checkbox with label in the document
var checkbox = TestUtils.renderIntoDocument(
<CheckboxWithLabel labelOn="On" labelOff="Off" />
);
var checkboxNode …Run Code Online (Sandbox Code Playgroud) 编辑:错误解决了!我在if()之后放了一个分号.谢谢保罗!
我刚刚到达这个奇怪的情况(该片段可以在http://jsfiddle.net/nUs7h/运行):
function check_if_tag_used()
{
var found = false;
return found;
}
var used = check_if_tag_used();
console.debug(used);
if (used);
{
alert("This should not appear!"); // why this runs?
}
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尽管如果假的是使用变量的值,为什么会显示alert()?请注意,console.debug()确实将其报告为false.