Console

The console module provides a simple debugging console, which is similar to the JavaScript console provided by the browser.

NOTE

The initial APIs of this module are supported since API version 3. Newly added APIs will be marked with a superscript to indicate their earliest API version.

console.debug

debug(message: string, …arguments: any[]): void

Prints debugging information in formatted output mode.

Since API version 9, this API is supported in ArkTS widgets.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Example

const number = 5;
console.debug('count: %d', number);  // Print the debugging information with arguments in the message replaced.
// count: 5 
console.debug('count:', number);  // Print the message and other information.
// count: 5 
console.debug('count:'); // Print the message only.
// count: 

console.log

log(message: string, …arguments: any[]): void

Prints log information in formatted output mode.

Since API version 9, this API is supported in ArkTS widgets.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Example

const number = 5;
console.log('count: %d', number);  // Print the log information with arguments in the message replaced.
// count: 5 
console.log('count:', number);  // Print the message and other information.
// count: 5 
console.log('count:'); // Print the message only.
// count: 

console.info

info(message: string, …arguments: any[]): void

Prints log information in formatted output mode. This API is the alias of console.log ().

Since API version 9, this API is supported in ArkTS widgets.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Example

const number = 5;
console.info('count: %d', number);  // Print the log information with arguments in the message replaced.
// count: 5 
console.info('count:', number);  // Print the message and other information.
// count: 5 
console.info('count:'); // Print the message only.
// count: 

console.warn

warn(message: string, …arguments: any[]): void

Prints warning information in formatted output mode.

Since API version 9, this API is supported in ArkTS widgets.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Example

const str = "name should be string";
console.warn('warn: %d', str); // Print the warning information with arguments in the message replaced.
// warn: name should be string
console.warn('warn:', str);  // Print the message and other information.
// warn: name should be string
console.warn('warn:'); // Print the message only.
// warn: 

console.error

error(message: string, …arguments: any[]): void

Prints error information in formatted output mode.

Since API version 9, this API is supported in ArkTS widgets.

System capability: SystemCapability.ArkUI.ArkUI.Full

Parameters

Example

const str = "value is not defined";
console.error('error: %d', str);  // Print the error information with arguments in the message replaced.
// error: value is not defined
console.error('error:', str);  // Print the message and other information.
// error: value is not defined
console.error('error:'); // Print the message only.
// error: 

console.assert¹⁰⁺

assert(value?: Object, …arguments: Object[]): void

Prints assertion information.

System capability: SystemCapability.Utils.Lang

Parameters

Example

console.assert(true, 'does nothing');  // Do not print error information as value is true.
console.assert(2% 1 == 0,'does nothing');  // Do not print error information as value is true.

console.assert(false, 'console %s work', 'didn\'t');
// Assertion failed: console didn't work

console.assert();
// Assertion failed

console.count¹⁰⁺

count(label?: string): void

Maintains an internal counter. When this counter is invoked, its label name and the corresponding call count are printed.

System capability: SystemCapability.Utils.Lang

Parameters

Example

console.count()
// default: 1
console.count('default')
// default: 2
console.count('abc')
// abc: 1
console.count('xyz')
// xyz: 1
console.count('abc')
// abc: 2
console.count()
// default: 3

console.countReset¹⁰⁺

countReset(label?: string): void

Resets a counter based on the specified label name.

System capability: SystemCapability.Utils.Lang

Parameters

Example

console.count('abc');
// abc: 1
console.countReset('abc');
console.count('abc');
// abc: 1

console.dir¹⁰⁺

dir(dir?: Object): void

Prints content of the specified object.

System capability: SystemCapability.Utils.Lang

Parameters

Example

class bar {
  baz: boolean = true;
}
let b: bar = {baz: true}
class foo{
  bar: bar = b;
}
let c: foo = {bar: b}
class  c1{
  foo: foo = c;
}
let a: c1 = {foo: c}
console.dir(a);
// Object: {"foo":{"bar":{"baz":true}}}

console.dir(); // No information is printed.

console.dirxml¹⁰⁺

dirxml(…arguments: Object[]): void

Displays an interactive tree of the descendant elements of the specified XML element. This API is implemented by calling console.log() internally. It does not produce any XML elements. The usage method is the same as that of console.log().

System capability: SystemCapability.Utils.Lang

Parameters

Example

const number = 5;
console.dirxml('count: %d', number);
// count: 5 
console.dirxml('count:', number);
// count: 5 
console.dirxml('count:');
// count: 

console.group¹⁰⁺

group(…arguments: Object[]): void

Increases the indentation of subsequent lines by two spaces. If the information to be printed is provided, the information is printed without extra indentation.

System capability: SystemCapability.Utils.Lang

Parameters

Example

console.log("outter");
// outter
console.group();
console.log("level 1");
//   level 1
console.group("in level1");
//   in level1
console.log("level 2");
//     level 2

console.groupCollapsed¹⁰⁺

groupCollapsed(…arguments: Object[]): void

Creates a new inline group in collapsed mode. The usage and function of this API are the same as those of console.group().

System capability: SystemCapability.Utils.Lang

Parameters

Example

console.groupCollapsed("outter");
// outter
console.groupCollapsed();
console.log("level 1");
//   level 1
console.groupCollapsed("in level1");
//   in level1
console.log("level 2");
//     level 2

console.groupEnd¹⁰⁺

groupEnd(): void

Reduces the indentation of subsequent lines by two spaces.

System capability: SystemCapability.Utils.Lang

Example

console.log("outter");
// outter
console.group();
console.log("level 1");
//   level 1
console.groupEnd();
console.log("outter");
// outter

console.table¹⁰⁺

table(tableData?: Object): void

Prints data in a table.

System capability: SystemCapability.Utils.Lang

Parameters

Example

console.table([1, 2, 3]);
// ┌─────────┬────────┐
// │ (index) │ Values │
// ├─────────┼────────┤
// │    0    │   1    │
// │    1    │   2    │
// │    2    │   3    │ 
// └─────────┴────────┘

console.table({ a: [1, 2, 3, 4, 5], b: 5, c: { e: 5 } });

// ┌─────────┬───┬───┬───┬───┬───┬───┬────────┐
// │ (index) │ 0 │ 1 │ 2 │ 3 │ 4 │ e │ Values │
// ├─────────┼───┼───┼───┼───┼───┼───┼────────┤
// │    a    │ 1 │ 2 │ 3 │ 4 │ 5 │   │        │
// │    b    │   │   │   │   │   │   │   5    │
// │    c    │   │   │   │   │   │ 5 │        │
// └─────────┴───┴───┴───┴───┴───┴───┴────────┘

console.time¹⁰⁺

time(label?: string): void

Starts a timer to track the duration of an operation. You can use console.timeEnd() to close the timer and print the elapsed time (in ms).

System capability: SystemCapability.Utils.Lang

Parameters

Example

console.time('abc');

console.timeEnd¹⁰⁺

timeEnd(label?: string): void

Stops the timer started by calling console.time() and prints the elapsed time (in ms).

System capability: SystemCapability.Utils.Lang

Parameters

Example

console.time('abc');
console.timeEnd('abc');
// abc: 225.438ms

console.timeLog¹⁰⁺

timeLog(label?: string, …arguments: Object[]): void

Prints the elapsed time and other data parameters for the timer started by console.time().

System capability: SystemCapability.Utils.Lang

Parameters

Example

console.time('timer1');
console.timeLog('timer1', 17);
// timer1: 365.227ms 17
console.timeEnd('timer1');
// timer1: 513.22ms

console.trace¹⁰⁺

trace(…arguments: Object[]): void

Creates a stack trace.

System capability: SystemCapability.Utils.Lang

Parameters

Example

console.trace();
// Trace:
//     xxxxxxxxxx (current stack information)
console.trace("Show the trace");
// Trace: Show the trace
//     xxxxxxxxxx (current stack information)

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