How to solve "SyntaxError: Unexpected token <=" in Vue application?

How to solve "SyntaxError: Unexpected token "<=" in a Vue application?

When you use template syntax, expression binding or related logical judgments in a Vue application, it is inevitable that There will be some syntax errors, the most common of which is the "SyntaxError: Unexpected token" error, but the specific solutions vary depending on the situation.

In the Vue application, "SyntaxError: Unexpected token" appears <=" errors are usually caused by the use of illegal characters or illegal syntax in the template syntax, causing the compiler to not parse them correctly.

Below, we will introduce some common problems related to syntax errors And corresponding solutions:

1. Using illegal JavaScript expressions in templates

Using illegal JavaScript expressions in templates is a common mistake , "SyntaxError: Unexpected token" error usually occurs in Vue applications. For example, the result of using JavaScript to calculate 1 1 in the Vue template is as follows:

<template>
  <div>{{1+1}}</div>
</template>

However, the '=' operator included in the expression is Illegal:

<template>
  <div>{{age=18}}</div>
</template>

In this example, inclusion of the "=" operator in the expression triggers a "SyntaxError: Unexpected token=" exception and prevents the compiler from correctly parsing the expression. To resolve this issue, We need to use normal JavaScript expressions:

<template>
  <div>{{age==18}}</div>
</template>

2. Illegal brackets are used in the template

Using illegal brackets in the template usually results in "SyntaxError: Unexpected token" exception. For example, using brackets in a Vue template is as follows:

<template>
  <div>{{ foo = ( bar + baz ) }}</div>
</template>

In this example, the compiler will raise a "SyntaxError: Unexpected token =" exception because the brackets are not necessary and should be removed .

<template>
  <div>{{foo = bar + baz}}</div>
</template>

3. Spaces or newlines are used in the template

In Vue applications, syntax errors may also be caused by invalid whitespace characters or fault tolerances in the template. Measures. For example, repeated spaces, extra newlines, whitespace tokens, or unended comments will cause the compiler to issue an error.

In the example below, our template contains extra whitespace tokens:

<template>
  <div>
    {{foo}}
  </div>
</template>

In this example, the template contains extra whitespace characters at the beginning and end, which will trigger errors such as "SyntaxError: Unexpected token "{" or "SyntaxError: Unexpected token"}". To solve this problem, we should remove the extra spaces or what we call whitespace marks.

<template>
  <div>{{foo}}</div>
</template>

Summary:

Encountering a syntax error is not a terrible thing. We only need to carefully observe the error message and identify which line has the error. Usually, errors occur because of problems with writing. The problem can be solved by deleting invalid characters, correcting incorrect expressions, and arranging the order of statements. Revisiting the code is the key to solving the problem. In the process of constantly modifying the code, we are also making continuous progress.

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