TypeScript babel-types.assignmentExpression函数代码示例

export function evalClass (ast: t.File, props = '', isRequire = false) {
  let mainClass!: t.ClassDeclaration
  const statements = new Set<t.ExpressionStatement>([
    template('Current.inst = this;')() as any
  ])

  traverse(ast, {
    ClassDeclaration (path) {
      mainClass = path.node
    },
    /**
     * 目前 node 的版本支持不了 class-properties
     * 但 babel 又有 bug，某些情况竟然把转换后的 class-properties 编译到 super 之前
     * 不然用 babel.transformFromAst 就完事了
     * 现在只能自己实现这个 feature 的部分功能了，真 tm 麻烦
     * @TODO 有空再给他们提 PR 吧
     */
    ClassProperty (path) {
      const { key, value } = path.node
      statements.add(t.expressionStatement(t.assignmentExpression(
        '=',
        t.memberExpression(
          t.thisExpression(),
          key
        ),
        value
      )))
      path.remove()
    }
  })

  for (const method of mainClass.body.body) {
    // constructor 即便没有被定义也会被加上
    if (t.isClassMethod(method) && method.kind === 'constructor') {
      const index = method.body.body.findIndex(node => t.isSuper(node))
      method.body.body.push(
        t.expressionStatement(t.assignmentExpression(
          '=',
          t.memberExpression(
            t.thisExpression(),
            t.identifier('state')
          ),
          t.callExpression(t.memberExpression(t.thisExpression(), t.identifier('_createData')), [])
        ))
      )
      method.body.body.splice(index, 0, ...statements)
    }
  }

  let code = `function f() {};` +
    generate(t.classDeclaration(t.identifier('Test'), t.identifier('f'), mainClass.body, [])).code +
    ';' + `var classInst =  new Test(${props});classInst`

  code = internalFunction + code

  // tslint:disable-next-line
  return eval(code)
}

export function generateAnonymousState (
  scope: Scope,
  expression: NodePath<t.Expression>,
  refIds: Set<t.Identifier>,
  isLogical?: boolean
) {
  let variableName = `anonymousState_${scope.generateUid()}`
  let statementParent = expression.getStatementParent()
  if (!statementParent) {
    throw codeFrameError(expression.node.loc, '无法生成匿名 State，尝试先把值赋到一个变量上再把变量调换。')
  }
  const jsx = isLogical ? expression : expression.findParent(p => p.isJSXElement())
  const callExpr = jsx.findParent(p => p.isCallExpression() && isArrayMapCallExpression(p)) as NodePath<t.CallExpression>
  const ifExpr = jsx.findParent(p => p.isIfStatement())
  const blockStatement = jsx.findParent(p => p.isBlockStatement() && p.parentPath === ifExpr) as NodePath<t.BlockStatement>
  const expr = setParentCondition(jsx, cloneDeep(expression.node))
  if (!callExpr) {
    refIds.add(t.identifier(variableName))
    statementParent.insertBefore(
      buildConstVariableDeclaration(variableName, expr)
    )
    if (blockStatement && blockStatement.isBlockStatement()) {
      blockStatement.traverse({
        VariableDeclarator: (path) => {
          const { id, init } = path.node
          const isArrowFunctionInJSX = path.findParent(p => p.isJSXAttribute() ||
            (
              p.isAssignmentExpression() && t.isMemberExpression(p.node.left) && t.isThisExpression(p.node.left.object)
                && t.isIdentifier(p.node.left.property) && p.node.left.property.name.startsWith('')
            )
          )
          if (isArrowFunctionInJSX) {
            return
          }
          if (t.isIdentifier(id) && !id.name.startsWith(LOOP_STATE)) {
            const newId = scope.generateDeclaredUidIdentifier('$' + id.name)
            refIds.forEach((refId) => {
              if (refId.name === variableName && !variableName.startsWith('_$')) {
                refIds.delete(refId)
              }
            })
            variableName = newId.name
            if (Adapter.type === Adapters.quickapp && variableName.startsWith('_$')) {
              const newVarName = variableName.slice(2)
              scope.rename(variableName, newVarName)
              variableName = newVarName
            }
            refIds.add(t.identifier(variableName))
            blockStatement.scope.rename(id.name, newId.name)
            path.parentPath.replaceWith(
              template('ID = INIT;')({ ID: newId, INIT: init })
            )
          }
        }
      })
    }
  } else {
    variableName = `${LOOP_STATE}_${callExpr.scope.generateUid()}`
    const func = callExpr.node.arguments[0]
    if (t.isArrowFunctionExpression(func)) {
      if (!t.isBlockStatement(func.body)) {
        func.body = t.blockStatement([
          buildConstVariableDeclaration(variableName, expr),
          t.returnStatement(func.body)
        ])
      } else {
        if (ifExpr && ifExpr.isIfStatement() && ifExpr.findParent(p => p === callExpr)) {
          const consequent = ifExpr.get('consequent')
          const test = ifExpr.get('test')
          if (consequent.isBlockStatement()) {
            if (jsx === test || jsx.findParent(p => p === test)) {
              func.body.body.unshift(buildConstVariableDeclaration(variableName, expr))
            } else {
              func.body.body.unshift(t.variableDeclaration('let', [t.variableDeclarator(t.identifier(variableName), t.nullLiteral())]))
              consequent.node.body.push(t.expressionStatement(t.assignmentExpression(
                '=',
                t.identifier(variableName),
                expr
              )))
            }
          } else {
            throw codeFrameError(consequent.node, 'if 表达式的结果必须由一个花括号包裹')
          }
        } else {
          func.body.body.splice(func.body.body.length - 1, 0, buildConstVariableDeclaration(variableName, expr))
        }
      }
    }
  }
  const id = t.identifier(variableName)
  expression.replaceWith(id)
  return id
}