@posprint/command-builder
v0.0.50
Published
JavaScript library that implements the ESC/POS and TSC protocol to buffer.
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ESC/POS TSC Buffer Builder
JavaScript library that implements the ESC/POS and TSC protocol to buffer, also provides an AST like JSON tree structure that you can preparing convertible templates (hmtl/xml) as you want.
Features
- ESC/POS and TSC protocol compatible
- Root, text, table, tr, td, img, blank, separator and qrcode nodes include style attribues implementation
- Command node for cashbox and cut paper implementation
- Compile semantic nodes to raw buffer according to ESC/POS and TSC protocol
Usage
- Installation of nodejs environment
npm install @posprint/command-builder
The library is distributed as umd package, just import to your front-end project the normally.
- Build json tree to command buffer
Build ESC command buffer from json tree
const { buildCommand } = require('@posprint/command-builder')
const jsonTree = {
"elementName": "root",
"attributes":{},
"children": [{
"elementName": "blank",
"attributes":{},
"children": null
},
{
"elementName": "text",
"attributes": {
"font-size": "wide-high",
"align": "center"
},
"children": "Change Table"
}]
}
const cmd = await buildCommand(jsonTree, { type: 'esc', encoding: 'UTF-8', paperSize: [80]})
const buffer = commands.getBuffer().flush()
After json tree is built by command bulder, pass buffer to printer tcp socket directly for printing.
Build TSC command buffer from json tree
const { buildCommand } = require('@posprint/command-builder')
{
"elementName": "root",
"attributes":{},
"children": [
{
"elementName": "text",
"attributes":
{
"align": "center"
},
"children": "---Order List---"
},
{
"elementName": "text",
"attributes":{},
"children": "Latte"
},
{
"elementName": "text",
"attributes":
{},
"children": "Take out"
},
{
"elementName": "separator",
"attributes":
{},
"children": null
},
{
"elementName": "text",
"attributes":
{},
"children": "05-18 14:29 #498"
},
]
}
const cmd = await buildCommand(jsonTree, { type: 'tsc', encoding: 'UTF-8', paperSize: [40, 30]})
const buffer = commands.getBuffer().flush()
Tsc only supports text
, separator
and root
right now, other nodes will be ignored when you printer type is TSC. We are extending more tsc nodes, for example table, img, blank.
- Send raw buffer to printer through tcp connection
View example folder to get demo and screenshot how to buffer be printed by physical printer.
API
buildCommand
buildCommand(json, option)
- json: json tree structure of nodes, view node tree description below
- object.type: string type allows 'esc' and 'tsc', default value is 'esc'
- object.encoding: string type of encoding, default value is 'UTF-8'
- object.paperSize: array type of printer paper size, 'tsc' type contains two elements, default value is [80]. ie, [80], [58], [40, 30]
Returns a Template instance which can invoke getBuffer() method to get raw buffer.
validateNode
validateNode(json, option)
- json, option parameters are the same as
buildCommand
, the difference is json tree not be built buffer in order to validate json tree of nodes
Node Json Tree
Json tree that contains multiple nodes
must have a root node, each node contains elementName
, attributes
, children
and other attributes.
The specific json tree format is as follows:
{
"elementName": "root",
"attributes": {},
"children": [{
"elementName": "blank",
"attributes": {},
"children": null
},
{
"elementName": "text",
"attributes":
{
"align": "center"
},
"children": "Order List"
}
]
}
node
specification
| Attribute | Type | Requirement | specification | |-----|----|---|----| | elementName | string | required | A node describes a type of printing instruction, text, picture, QR code, etc. Allowed element name see supported nodes below. | | attributes | object | optional | Describe the style of the node, font, style, alignment, etc. | | children | array, string, null | optional | The content printed by printer or the child node. |
You can use different json parser to convert the HTML/XML or other source file into a json tree.
Supported Nodes
- root
- text
- command
- blank
- img
- qrcode
- separator
- table
- tr
- td
- section
Exmaples
View source code in the exmaples folder about ESC and TSC content printing.