Node.js-超出最大调用堆栈大小

您应该将递归函数调用包装到

• setTimeout

  ，

• setImmediate

  要么

• process.nextTick

函数使node.js有机会清除堆栈。如果您不这样做，并且有很多循环没有任何 真正的
异步函数调用，或者如果您不等待回调，那么您

RangeError: Maximum call stack size exceeded

有很多有关“潜在异步循环”的文章。这是一个。

现在再看一些示例代码：

// ANTI-PATTERN// THIS WILL CRASHvar condition = false, // potential means "maybe never"    max = 1000000;function potAsyncLoop( i, resume ) {    if( i < max ) {        if( condition ) {  someAsyncFunc( function( err, result ) {      potAsyncLoop( i+1, callback ); });        } else { // this will crash after some rounds with // "stack exceed", because control is never given back // to the browser  // -> no GC and browser "dead" ... "VERY BAD" potAsyncLoop( i+1, resume );         }    } else {        resume();    }}potAsyncLoop( 0, function() {    // pre after the loop    ...});

这是对的：

var condition = false, // potential means "maybe never"    max = 1000000;function potAsyncLoop( i, resume ) {    if( i < max ) {        if( condition ) {  someAsyncFunc( function( err, result ) {      potAsyncLoop( i+1, callback ); });        } else { // Now the browser gets the chance to clear the stack // after every round by getting the control back. // Afterwards the loop continues setTimeout( function() {     potAsyncLoop( i+1, resume );  }, 0 );        }    } else {        resume();    }}potAsyncLoop( 0, function() {    // pre after the loop    ...});

现在您的循环可能变得太慢，因为我们每回合会浪费一点时间（一次浏览器往返）。但是您不必

setTimeout

var condition = false, // potential means "maybe never"    max = 1000000;function potAsyncLoop( i, resume ) {    if( i < max ) {        if( condition ) {  someAsyncFunc( function( err, result ) {      potAsyncLoop( i+1, callback ); });        } else { if( i % 1000 === 0 ) {     setTimeout( function() {         potAsyncLoop( i+1, resume );      }, 0 ); } else {     potAsyncLoop( i+1, resume );  }        }    } else {        resume();    }}potAsyncLoop( 0, function() {    // pre after the loop    ...});