Version: 1.6.0

EvaluationArgument

Playwright evaluation methods like page.evaluate(pageFunction[, arg]) take a single optional argument. This argument can be a mix of Serializable values and JSHandle or ElementHandle instances. Handles are automatically converted to the value they represent.

See examples for various scenarios:

// A primitive value.
await page.evaluate(num => num, 42);
// An array.
await page.evaluate(array => array.length, [1, 2, 3]);
// An object.
await page.evaluate(object => object.foo, { foo: 'bar' });
// A single handle.
const button = await page.$('button');
await page.evaluate(button => button.textContent, button);
// Alternative notation using elementHandle.evaluate.
await button.evaluate((button, from) => button.textContent.substring(from), 5);
// Object with multiple handles.
const button1 = await page.$('.button1');
const button2 = await page.$('.button2');
await page.evaluate(
o => o.button1.textContent + o.button2.textContent,
{ button1, button2 });
// Obejct destructuring works. Note that property names must match
// between the destructured object and the argument.
// Also note the required parenthesis.
await page.evaluate(
({ button1, button2 }) => button1.textContent + button2.textContent,
{ button1, button2 });
// Array works as well. Arbitrary names can be used for destructuring.
// Note the required parenthesis.
await page.evaluate(
([b1, b2]) => b1.textContent + b2.textContent,
[button1, button2]);
// Any non-cyclic mix of serializables and handles works.
await page.evaluate(
x => x.button1.textContent + x.list[0].textContent + String(x.foo),
{ button1, list: [button2], foo: null });