error-detector.js
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/* @flow */
import { dirRE } from './parser/index'
// operators like typeof, instanceof and in are allowed
const prohibitedKeywordRE = new RegExp('\\b' + (
'do,if,for,let,new,try,var,case,else,with,await,break,catch,class,const,' +
'super,throw,while,yield,delete,export,import,return,switch,default,' +
'extends,finally,continue,debugger,function,arguments'
).split(',').join('\\b|\\b') + '\\b')
// check valid identifier for v-for
const identRE = /[A-Za-z_$][\w$]*/
// strip strings in expressions
const stripStringRE = /'(?:[^'\\]|\\.)*'|"(?:[^"\\]|\\.)*"|`(?:[^`\\]|\\.)*\$\{|\}(?:[^`\\]|\\.)*`|`(?:[^`\\]|\\.)*`/g
// detect problematic expressions in a template
export function detectErrors (ast: ?ASTNode): Array<string> {
const errors: Array<string> = []
if (ast) {
checkNode(ast, errors)
}
return errors
}
function checkNode (node: ASTNode, errors: Array<string>) {
if (node.type === 1) {
for (const name in node.attrsMap) {
if (dirRE.test(name)) {
const value = node.attrsMap[name]
if (value) {
if (name === 'v-for') {
checkFor(node, `v-for="${value}"`, errors)
} else {
checkExpression(value, `${name}="${value}"`, errors)
}
}
}
}
if (node.children) {
for (let i = 0; i < node.children.length; i++) {
checkNode(node.children[i], errors)
}
}
} else if (node.type === 2) {
checkExpression(node.expression, node.text, errors)
}
}
function checkFor (node: ASTElement, text: string, errors: Array<string>) {
checkExpression(node.for || '', text, errors)
checkIdentifier(node.alias, 'v-for alias', text, errors)
checkIdentifier(node.iterator1, 'v-for iterator', text, errors)
checkIdentifier(node.iterator2, 'v-for iterator', text, errors)
}
function checkIdentifier (ident: ?string, type: string, text: string, errors: Array<string>) {
if (typeof ident === 'string' && !identRE.test(ident)) {
errors.push(`- invalid ${type} "${ident}" in expression: ${text}`)
}
}
function checkExpression (exp: string, text: string, errors: Array<string>) {
try {
new Function(`return ${exp}`)
} catch (e) {
const keywordMatch = exp.replace(stripStringRE, '').match(prohibitedKeywordRE)
if (keywordMatch) {
errors.push(
`- avoid using JavaScript keyword as property name: ` +
`"${keywordMatch[0]}" in expression ${text}`
)
} else {
errors.push(`- invalid expression: ${text}`)
}
}
}